diff --git a/CODEOWNERS b/CODEOWNERS
index d1bda212d2d..8a2ea23ded9 100644
--- a/CODEOWNERS
+++ b/CODEOWNERS
@@ -421,6 +421,7 @@ homeassistant/components/smappee/* @bsmappee
 homeassistant/components/smart_meter_texas/* @grahamwetzler
 homeassistant/components/smarthab/* @outadoc
 homeassistant/components/smartthings/* @andrewsayre
+homeassistant/components/smarttub/* @mdz
 homeassistant/components/smarty/* @z0mbieprocess
 homeassistant/components/sms/* @ocalvo
 homeassistant/components/smtp/* @fabaff
diff --git a/homeassistant/components/smarttub/__init__.py b/homeassistant/components/smarttub/__init__.py
new file mode 100644
index 00000000000..85298a75f65
--- /dev/null
+++ b/homeassistant/components/smarttub/__init__.py
@@ -0,0 +1,54 @@
+"""SmartTub integration."""
+import asyncio
+import logging
+
+from .const import DOMAIN, SMARTTUB_CONTROLLER
+from .controller import SmartTubController
+
+_LOGGER = logging.getLogger(__name__)
+
+PLATFORMS = ["climate"]
+
+
+async def async_setup(hass, _config):
+    """Set up smarttub component."""
+
+    hass.data.setdefault(DOMAIN, {})
+
+    return True
+
+
+async def async_setup_entry(hass, entry):
+    """Set up a smarttub config entry."""
+
+    controller = SmartTubController(hass)
+    hass.data[DOMAIN][entry.entry_id] = {
+        SMARTTUB_CONTROLLER: controller,
+    }
+
+    if not await controller.async_setup_entry(entry):
+        return False
+
+    for platform in PLATFORMS:
+        hass.async_create_task(
+            hass.config_entries.async_forward_entry_setup(entry, platform)
+        )
+
+    return True
+
+
+async def async_unload_entry(hass, entry):
+    """Remove a smarttub config entry."""
+    if not all(
+        await asyncio.gather(
+            *[
+                hass.config_entries.async_forward_entry_unload(entry, platform)
+                for platform in PLATFORMS
+            ]
+        )
+    ):
+        return False
+
+    hass.data[DOMAIN].pop(entry.entry_id)
+
+    return True
diff --git a/homeassistant/components/smarttub/climate.py b/homeassistant/components/smarttub/climate.py
new file mode 100644
index 00000000000..5f16bea8cf7
--- /dev/null
+++ b/homeassistant/components/smarttub/climate.py
@@ -0,0 +1,116 @@
+"""Platform for climate integration."""
+import logging
+
+from homeassistant.components.climate import ClimateEntity
+from homeassistant.components.climate.const import (
+    CURRENT_HVAC_HEAT,
+    CURRENT_HVAC_IDLE,
+    HVAC_MODE_HEAT,
+    SUPPORT_TARGET_TEMPERATURE,
+)
+from homeassistant.const import ATTR_TEMPERATURE, TEMP_CELSIUS
+from homeassistant.util.temperature import convert as convert_temperature
+
+from .const import DEFAULT_MAX_TEMP, DEFAULT_MIN_TEMP, DOMAIN, SMARTTUB_CONTROLLER
+from .entity import SmartTubEntity
+
+_LOGGER = logging.getLogger(__name__)
+
+
+async def async_setup_entry(hass, entry, async_add_entities):
+    """Set up climate entity for the thermostat in the tub."""
+
+    controller = hass.data[DOMAIN][entry.entry_id][SMARTTUB_CONTROLLER]
+
+    entities = [
+        SmartTubThermostat(controller.coordinator, spa) for spa in controller.spas
+    ]
+
+    async_add_entities(entities)
+
+
+class SmartTubThermostat(SmartTubEntity, ClimateEntity):
+    """The target water temperature for the spa."""
+
+    def __init__(self, coordinator, spa):
+        """Initialize the entity."""
+        super().__init__(coordinator, spa, "thermostat")
+
+    @property
+    def unique_id(self) -> str:
+        """Return a unique id for the entity."""
+        return f"{self.spa.id}-{self._entity_type}"
+
+    @property
+    def temperature_unit(self):
+        """Return the unit of measurement used by the platform."""
+        return TEMP_CELSIUS
+
+    @property
+    def hvac_action(self):
+        """Return the current running hvac operation."""
+        heater_status = self.get_spa_status("heater")
+        if heater_status == "ON":
+            return CURRENT_HVAC_HEAT
+        if heater_status == "OFF":
+            return CURRENT_HVAC_IDLE
+        return None
+
+    @property
+    def hvac_modes(self):
+        """Return the list of available hvac operation modes."""
+        return [HVAC_MODE_HEAT]
+
+    @property
+    def hvac_mode(self):
+        """Return the current hvac mode.
+
+        SmartTub devices don't seem to have the option of disabling the heater,
+        so this is always HVAC_MODE_HEAT.
+        """
+        return HVAC_MODE_HEAT
+
+    async def async_set_hvac_mode(self, hvac_mode: str):
+        """Set new target hvac mode.
+
+        As with hvac_mode, we don't really have an option here.
+        """
+        if hvac_mode == HVAC_MODE_HEAT:
+            return
+        raise NotImplementedError(hvac_mode)
+
+    @property
+    def min_temp(self):
+        """Return the minimum temperature."""
+        min_temp = DEFAULT_MIN_TEMP
+        return convert_temperature(min_temp, TEMP_CELSIUS, self.temperature_unit)
+
+    @property
+    def max_temp(self):
+        """Return the maximum temperature."""
+        max_temp = DEFAULT_MAX_TEMP
+        return convert_temperature(max_temp, TEMP_CELSIUS, self.temperature_unit)
+
+    @property
+    def supported_features(self):
+        """Return the set of supported features.
+
+        Only target temperature is supported.
+        """
+        return SUPPORT_TARGET_TEMPERATURE
+
+    @property
+    def current_temperature(self):
+        """Return the current water temperature."""
+        return self.get_spa_status("water.temperature")
+
+    @property
+    def target_temperature(self):
+        """Return the target water temperature."""
+        return self.get_spa_status("setTemperature")
+
+    async def async_set_temperature(self, **kwargs):
+        """Set new target temperature."""
+        temperature = kwargs[ATTR_TEMPERATURE]
+        await self.spa.set_temperature(temperature)
+        await self.coordinator.async_refresh()
diff --git a/homeassistant/components/smarttub/config_flow.py b/homeassistant/components/smarttub/config_flow.py
new file mode 100644
index 00000000000..8f3ed17f93a
--- /dev/null
+++ b/homeassistant/components/smarttub/config_flow.py
@@ -0,0 +1,53 @@
+"""Config flow to configure the SmartTub integration."""
+import logging
+
+from smarttub import LoginFailed
+import voluptuous as vol
+
+from homeassistant import config_entries
+from homeassistant.const import CONF_EMAIL, CONF_PASSWORD
+
+from .const import DOMAIN  # pylint: disable=unused-import
+from .controller import SmartTubController
+
+DATA_SCHEMA = vol.Schema(
+    {vol.Required(CONF_EMAIL): str, vol.Required(CONF_PASSWORD): str}
+)
+
+
+_LOGGER = logging.getLogger(__name__)
+
+
+class SmartTubConfigFlow(config_entries.ConfigFlow, domain=DOMAIN):
+    """SmartTub configuration flow."""
+
+    VERSION = 1
+    CONNECTION_CLASS = config_entries.CONN_CLASS_CLOUD_POLL
+
+    async def async_step_user(self, user_input=None):
+        """Handle a flow initiated by the user."""
+        errors = {}
+
+        if user_input is None:
+            return self.async_show_form(
+                step_id="user", data_schema=DATA_SCHEMA, errors=errors
+            )
+
+        controller = SmartTubController(self.hass)
+        try:
+            account = await controller.login(
+                user_input[CONF_EMAIL], user_input[CONF_PASSWORD]
+            )
+        except LoginFailed:
+            errors["base"] = "invalid_auth"
+            return self.async_show_form(
+                step_id="user", data_schema=DATA_SCHEMA, errors=errors
+            )
+
+        existing_entry = await self.async_set_unique_id(account.id)
+        if existing_entry:
+            self.hass.config_entries.async_update_entry(existing_entry, data=user_input)
+            await self.hass.config_entries.async_reload(existing_entry.entry_id)
+            return self.async_abort(reason="reauth_successful")
+
+        return self.async_create_entry(title=user_input[CONF_EMAIL], data=user_input)
diff --git a/homeassistant/components/smarttub/const.py b/homeassistant/components/smarttub/const.py
new file mode 100644
index 00000000000..99e7f21f86d
--- /dev/null
+++ b/homeassistant/components/smarttub/const.py
@@ -0,0 +1,14 @@
+"""smarttub constants."""
+
+DOMAIN = "smarttub"
+
+EVENT_SMARTTUB = "smarttub"
+
+SMARTTUB_CONTROLLER = "smarttub_controller"
+
+SCAN_INTERVAL = 60
+
+POLLING_TIMEOUT = 10
+
+DEFAULT_MIN_TEMP = 18.5
+DEFAULT_MAX_TEMP = 40
diff --git a/homeassistant/components/smarttub/controller.py b/homeassistant/components/smarttub/controller.py
new file mode 100644
index 00000000000..31fe71d14b6
--- /dev/null
+++ b/homeassistant/components/smarttub/controller.py
@@ -0,0 +1,110 @@
+"""Interface to the SmartTub API."""
+
+import asyncio
+from datetime import timedelta
+import logging
+
+from aiohttp import client_exceptions
+import async_timeout
+from smarttub import APIError, LoginFailed, SmartTub
+from smarttub.api import Account
+
+from homeassistant.const import CONF_EMAIL, CONF_PASSWORD
+from homeassistant.exceptions import ConfigEntryNotReady
+from homeassistant.helpers import device_registry as dr
+from homeassistant.helpers.aiohttp_client import async_get_clientsession
+from homeassistant.helpers.update_coordinator import DataUpdateCoordinator, UpdateFailed
+
+from .const import DOMAIN, POLLING_TIMEOUT, SCAN_INTERVAL
+from .helpers import get_spa_name
+
+_LOGGER = logging.getLogger(__name__)
+
+
+class SmartTubController:
+    """Interface between Home Assistant and the SmartTub API."""
+
+    def __init__(self, hass):
+        """Initialize an interface to SmartTub."""
+        self._hass = hass
+        self._account = None
+        self.spas = set()
+        self._spa_devices = {}
+
+        self.coordinator = None
+
+    async def async_setup_entry(self, entry):
+        """Perform initial setup.
+
+        Authenticate, query static state, set up polling, and otherwise make
+        ready for normal operations .
+        """
+
+        try:
+            self._account = await self.login(
+                entry.data[CONF_EMAIL], entry.data[CONF_PASSWORD]
+            )
+        except LoginFailed:
+            # credentials were changed or invalidated, we need new ones
+
+            return False
+        except (
+            asyncio.TimeoutError,
+            client_exceptions.ClientOSError,
+            client_exceptions.ServerDisconnectedError,
+            client_exceptions.ContentTypeError,
+        ) as err:
+            raise ConfigEntryNotReady from err
+
+        self.spas = await self._account.get_spas()
+
+        self.coordinator = DataUpdateCoordinator(
+            self._hass,
+            _LOGGER,
+            name=DOMAIN,
+            update_method=self.async_update_data,
+            update_interval=timedelta(seconds=SCAN_INTERVAL),
+        )
+
+        await self.coordinator.async_refresh()
+
+        await self.async_register_devices(entry)
+
+        return True
+
+    async def async_update_data(self):
+        """Query the API and return the new state."""
+
+        data = {}
+        try:
+            async with async_timeout.timeout(POLLING_TIMEOUT):
+                for spa in self.spas:
+                    data[spa.id] = {"status": await spa.get_status()}
+        except APIError as err:
+            raise UpdateFailed(err) from err
+
+        return data
+
+    async def async_register_devices(self, entry):
+        """Register devices with the device registry for all spas."""
+        device_registry = await dr.async_get_registry(self._hass)
+        for spa in self.spas:
+            device = device_registry.async_get_or_create(
+                config_entry_id=entry.entry_id,
+                identifiers={(DOMAIN, spa.id)},
+                manufacturer=spa.brand,
+                name=get_spa_name(spa),
+                model=spa.model,
+            )
+            self._spa_devices[spa.id] = device
+
+    async def login(self, email, password) -> Account:
+        """Retrieve the account corresponding to the specified email and password.
+
+        Returns None if the credentials are invalid.
+        """
+
+        api = SmartTub(async_get_clientsession(self._hass))
+
+        await api.login(email, password)
+        return await api.get_account()
diff --git a/homeassistant/components/smarttub/entity.py b/homeassistant/components/smarttub/entity.py
new file mode 100644
index 00000000000..95d89971cb7
--- /dev/null
+++ b/homeassistant/components/smarttub/entity.py
@@ -0,0 +1,64 @@
+"""SmartTub integration."""
+import logging
+
+import smarttub
+
+from homeassistant.helpers.update_coordinator import (
+    CoordinatorEntity,
+    DataUpdateCoordinator,
+)
+
+from .const import DOMAIN
+from .helpers import get_spa_name
+
+_LOGGER = logging.getLogger(__name__)
+
+PLATFORMS = ["climate"]
+
+
+class SmartTubEntity(CoordinatorEntity):
+    """Base class for SmartTub entities."""
+
+    def __init__(
+        self, coordinator: DataUpdateCoordinator, spa: smarttub.Spa, entity_type
+    ):
+        """Initialize the entity.
+
+        Given a spa id and a short name for the entity, we provide basic device
+        info, name, unique id, etc. for all derived entities.
+        """
+
+        super().__init__(coordinator)
+        self.spa = spa
+        self._entity_type = entity_type
+
+    @property
+    def device_info(self) -> str:
+        """Return device info."""
+        return {
+            "identifiers": {(DOMAIN, self.spa.id)},
+            "manufacturer": self.spa.brand,
+            "model": self.spa.model,
+        }
+
+    @property
+    def name(self) -> str:
+        """Return the name of the entity."""
+        spa_name = get_spa_name(self.spa)
+        return f"{spa_name} {self._entity_type}"
+
+    def get_spa_status(self, path):
+        """Retrieve a value from the data returned by Spa.get_status().
+
+        Nested keys can be specified by a dotted path, e.g.
+        status['foo']['bar'] is 'foo.bar'.
+        """
+
+        status = self.coordinator.data[self.spa.id].get("status")
+        if status is None:
+            return None
+
+        for key in path.split("."):
+            status = status[key]
+
+        return status
diff --git a/homeassistant/components/smarttub/helpers.py b/homeassistant/components/smarttub/helpers.py
new file mode 100644
index 00000000000..a6f2d09c38f
--- /dev/null
+++ b/homeassistant/components/smarttub/helpers.py
@@ -0,0 +1,8 @@
+"""Helper functions for SmartTub integration."""
+
+import smarttub
+
+
+def get_spa_name(spa: smarttub.Spa) -> str:
+    """Return the name of the specified spa."""
+    return f"{spa.brand} {spa.model}"
diff --git a/homeassistant/components/smarttub/manifest.json b/homeassistant/components/smarttub/manifest.json
new file mode 100644
index 00000000000..9735a3753b4
--- /dev/null
+++ b/homeassistant/components/smarttub/manifest.json
@@ -0,0 +1,12 @@
+{
+  "domain": "smarttub",
+  "name": "SmartTub",
+  "config_flow": true,
+  "documentation": "https://www.home-assistant.io/integrations/smarttub",
+  "dependencies": [],
+  "codeowners": ["@mdz"],
+  "requirements": [
+      "python-smarttub==0.0.6"
+  ],
+  "quality_scale": "platinum"
+}
diff --git a/homeassistant/components/smarttub/strings.json b/homeassistant/components/smarttub/strings.json
new file mode 100644
index 00000000000..0d52673a469
--- /dev/null
+++ b/homeassistant/components/smarttub/strings.json
@@ -0,0 +1,22 @@
+{
+  "config": {
+    "step": {
+      "user": {
+        "title": "Login",
+        "description": "Enter your SmartTub email address and password to login",
+        "data": {
+          "email": "[%key:common::config_flow::data::email%]",
+          "password": "[%key:common::config_flow::data::password%]"
+        }
+      }
+    },
+    "error": {
+      "invalid_auth": "[%key:common::config_flow::error::invalid_auth%]",
+      "unknown": "[%key:common::config_flow::error::unknown%]"
+    },
+    "abort": {
+      "already_configured": "[%key:common::config_flow::abort::already_configured_device%]",
+      "reauth_successful": "[%key:common::config_flow::abort::reauth_successful%]"
+    }
+  }
+}
diff --git a/homeassistant/components/smarttub/translations/en.json b/homeassistant/components/smarttub/translations/en.json
new file mode 100644
index 00000000000..4cf93091887
--- /dev/null
+++ b/homeassistant/components/smarttub/translations/en.json
@@ -0,0 +1,22 @@
+{
+    "config": {
+        "abort": {
+            "already_configured": "Device is already configured",
+            "reauth_successful": "Re-authentication was successful"
+        },
+        "error": {
+            "invalid_auth": "Invalid authentication",
+            "unknown": "Unexpected error"
+        },
+        "step": {
+            "user": {
+                "data": {
+                    "email": "Email",
+                    "password": "Password"
+                },
+                "description": "Enter your SmartTub email address and password to login",
+                "title": "Login"
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/homeassistant/generated/config_flows.py b/homeassistant/generated/config_flows.py
index 6ff72cf5572..400f2f2352b 100644
--- a/homeassistant/generated/config_flows.py
+++ b/homeassistant/generated/config_flows.py
@@ -197,6 +197,7 @@ FLOWS = [
     "smart_meter_texas",
     "smarthab",
     "smartthings",
+    "smarttub",
     "smhi",
     "sms",
     "solaredge",
diff --git a/requirements_all.txt b/requirements_all.txt
index 24bb508c713..de6c34f4feb 100644
--- a/requirements_all.txt
+++ b/requirements_all.txt
@@ -1809,6 +1809,9 @@ python-qbittorrent==0.4.2
 # homeassistant.components.ripple
 python-ripple-api==0.0.3
 
+# homeassistant.components.smarttub
+python-smarttub==0.0.6
+
 # homeassistant.components.sochain
 python-sochain-api==0.0.2
 
diff --git a/requirements_test_all.txt b/requirements_test_all.txt
index e22ab3fa0e2..4f15becca1a 100644
--- a/requirements_test_all.txt
+++ b/requirements_test_all.txt
@@ -934,6 +934,9 @@ python-nest==4.1.0
 # homeassistant.components.ozw
 python-openzwave-mqtt[mqtt-client]==1.4.0
 
+# homeassistant.components.smarttub
+python-smarttub==0.0.6
+
 # homeassistant.components.songpal
 python-songpal==0.12
 
diff --git a/tests/components/smarttub/__init__.py b/tests/components/smarttub/__init__.py
new file mode 100644
index 00000000000..afbf271eb63
--- /dev/null
+++ b/tests/components/smarttub/__init__.py
@@ -0,0 +1 @@
+"""Tests for the smarttub integration."""
diff --git a/tests/components/smarttub/conftest.py b/tests/components/smarttub/conftest.py
new file mode 100644
index 00000000000..fec74a2b30a
--- /dev/null
+++ b/tests/components/smarttub/conftest.py
@@ -0,0 +1,86 @@
+"""Common fixtures for smarttub tests."""
+
+from unittest.mock import create_autospec, patch
+
+import pytest
+import smarttub
+
+from homeassistant.components.smarttub.const import DOMAIN
+from homeassistant.components.smarttub.controller import SmartTubController
+from homeassistant.const import CONF_EMAIL, CONF_PASSWORD
+
+from tests.common import MockConfigEntry
+
+
+@pytest.fixture
+def config_data():
+    """Provide configuration data for tests."""
+    return {CONF_EMAIL: "test-email", CONF_PASSWORD: "test-password"}
+
+
+@pytest.fixture
+def config_entry(config_data):
+    """Create a mock config entry."""
+    return MockConfigEntry(
+        domain=DOMAIN,
+        data=config_data,
+        options={},
+    )
+
+
+@pytest.fixture(name="spa")
+def mock_spa():
+    """Mock a SmartTub.Spa."""
+
+    mock_spa = create_autospec(smarttub.Spa, instance=True)
+    mock_spa.id = "mockspa1"
+    mock_spa.brand = "mockbrand1"
+    mock_spa.model = "mockmodel1"
+    mock_spa.get_status.return_value = {
+        "setTemperature": 39,
+        "water": {"temperature": 38},
+        "heater": "ON",
+    }
+    return mock_spa
+
+
+@pytest.fixture(name="account")
+def mock_account(spa):
+    """Mock a SmartTub.Account."""
+
+    mock_account = create_autospec(smarttub.Account, instance=True)
+    mock_account.id = "mockaccount1"
+    mock_account.get_spas.return_value = [spa]
+    return mock_account
+
+
+@pytest.fixture(name="smarttub_api")
+def mock_api(account, spa):
+    """Mock the SmartTub API."""
+
+    with patch(
+        "homeassistant.components.smarttub.controller.SmartTub",
+        autospec=True,
+    ) as api_class_mock:
+        api_mock = api_class_mock.return_value
+        api_mock.get_account.return_value = account
+        yield api_mock
+
+
+@pytest.fixture
+async def controller(smarttub_api, hass, config_entry):
+    """Instantiate controller for testing."""
+
+    controller = SmartTubController(hass)
+    assert len(controller.spas) == 0
+    assert await controller.async_setup_entry(config_entry)
+
+    assert len(controller.spas) > 0
+
+    return controller
+
+
+@pytest.fixture
+async def coordinator(controller):
+    """Provide convenient access to the coordinator via the controller."""
+    return controller.coordinator
diff --git a/tests/components/smarttub/test_climate.py b/tests/components/smarttub/test_climate.py
new file mode 100644
index 00000000000..f0e6ced4abd
--- /dev/null
+++ b/tests/components/smarttub/test_climate.py
@@ -0,0 +1,74 @@
+"""Test the SmartTub climate platform."""
+
+from homeassistant.components.climate.const import (
+    ATTR_CURRENT_TEMPERATURE,
+    ATTR_HVAC_ACTION,
+    ATTR_HVAC_MODE,
+    ATTR_HVAC_MODES,
+    ATTR_MAX_TEMP,
+    ATTR_MIN_TEMP,
+    CURRENT_HVAC_HEAT,
+    CURRENT_HVAC_IDLE,
+    DOMAIN as CLIMATE_DOMAIN,
+    HVAC_MODE_HEAT,
+    SERVICE_SET_HVAC_MODE,
+    SERVICE_SET_TEMPERATURE,
+    SUPPORT_TARGET_TEMPERATURE,
+)
+from homeassistant.components.smarttub.const import DEFAULT_MAX_TEMP, DEFAULT_MIN_TEMP
+from homeassistant.const import (
+    ATTR_ENTITY_ID,
+    ATTR_SUPPORTED_FEATURES,
+    ATTR_TEMPERATURE,
+)
+
+
+async def test_thermostat(coordinator, spa, hass, config_entry):
+    """Test the thermostat entity."""
+
+    spa.get_status.return_value = {
+        "heater": "ON",
+        "water": {
+            "temperature": 38,
+        },
+        "setTemperature": 39,
+    }
+    config_entry.add_to_hass(hass)
+    await hass.config_entries.async_setup(config_entry.entry_id)
+    await hass.async_block_till_done()
+
+    entity_id = f"climate.{spa.brand}_{spa.model}_thermostat"
+    state = hass.states.get(entity_id)
+    assert state
+
+    assert state.attributes[ATTR_HVAC_ACTION] == CURRENT_HVAC_HEAT
+
+    spa.get_status.return_value["heater"] = "OFF"
+    await hass.helpers.entity_component.async_update_entity(entity_id)
+    state = hass.states.get(entity_id)
+
+    assert state.attributes[ATTR_HVAC_ACTION] == CURRENT_HVAC_IDLE
+
+    assert set(state.attributes[ATTR_HVAC_MODES]) == {HVAC_MODE_HEAT}
+    assert state.state == HVAC_MODE_HEAT
+    assert state.attributes[ATTR_SUPPORTED_FEATURES] == SUPPORT_TARGET_TEMPERATURE
+    assert state.attributes[ATTR_CURRENT_TEMPERATURE] == 38
+    assert state.attributes[ATTR_TEMPERATURE] == 39
+    assert state.attributes[ATTR_MAX_TEMP] == DEFAULT_MAX_TEMP
+    assert state.attributes[ATTR_MIN_TEMP] == DEFAULT_MIN_TEMP
+
+    await hass.services.async_call(
+        CLIMATE_DOMAIN,
+        SERVICE_SET_TEMPERATURE,
+        {ATTR_ENTITY_ID: entity_id, ATTR_TEMPERATURE: 37},
+        blocking=True,
+    )
+    spa.set_temperature.assert_called_with(37)
+
+    await hass.services.async_call(
+        CLIMATE_DOMAIN,
+        SERVICE_SET_HVAC_MODE,
+        {ATTR_ENTITY_ID: entity_id, ATTR_HVAC_MODE: HVAC_MODE_HEAT},
+        blocking=True,
+    )
+    # does nothing
diff --git a/tests/components/smarttub/test_config_flow.py b/tests/components/smarttub/test_config_flow.py
new file mode 100644
index 00000000000..a57eb43eef7
--- /dev/null
+++ b/tests/components/smarttub/test_config_flow.py
@@ -0,0 +1,64 @@
+"""Test the smarttub config flow."""
+from unittest.mock import patch
+
+from smarttub import LoginFailed
+
+from homeassistant import config_entries
+from homeassistant.components.smarttub.const import DOMAIN
+
+
+async def test_form(hass, smarttub_api):
+    """Test we get the form."""
+    result = await hass.config_entries.flow.async_init(
+        DOMAIN, context={"source": config_entries.SOURCE_USER}
+    )
+    assert result["type"] == "form"
+    assert result["errors"] == {}
+
+    with patch(
+        "homeassistant.components.smarttub.async_setup", return_value=True
+    ) as mock_setup, patch(
+        "homeassistant.components.smarttub.async_setup_entry",
+        return_value=True,
+    ) as mock_setup_entry:
+        result2 = await hass.config_entries.flow.async_configure(
+            result["flow_id"],
+            {"email": "test-email", "password": "test-password"},
+        )
+
+    assert result2["type"] == "create_entry"
+    assert result2["title"] == "test-email"
+    assert result2["data"] == {
+        "email": "test-email",
+        "password": "test-password",
+    }
+    await hass.async_block_till_done()
+    mock_setup.assert_called_once()
+    mock_setup_entry.assert_called_once()
+
+    result = await hass.config_entries.flow.async_init(
+        DOMAIN, context={"source": config_entries.SOURCE_USER}
+    )
+
+    result2 = await hass.config_entries.flow.async_configure(
+        result["flow_id"], {"email": "test-email2", "password": "test-password2"}
+    )
+    assert result2["type"] == "abort"
+    assert result2["reason"] == "reauth_successful"
+
+
+async def test_form_invalid_auth(hass, smarttub_api):
+    """Test we handle invalid auth."""
+    result = await hass.config_entries.flow.async_init(
+        DOMAIN, context={"source": config_entries.SOURCE_USER}
+    )
+
+    smarttub_api.login.side_effect = LoginFailed
+
+    result2 = await hass.config_entries.flow.async_configure(
+        result["flow_id"],
+        {"email": "test-email", "password": "test-password"},
+    )
+
+    assert result2["type"] == "form"
+    assert result2["errors"] == {"base": "invalid_auth"}
diff --git a/tests/components/smarttub/test_controller.py b/tests/components/smarttub/test_controller.py
new file mode 100644
index 00000000000..e59ad86c09e
--- /dev/null
+++ b/tests/components/smarttub/test_controller.py
@@ -0,0 +1,37 @@
+"""Test the SmartTub controller."""
+
+import pytest
+import smarttub
+
+from homeassistant.components.smarttub.controller import SmartTubController
+from homeassistant.helpers.update_coordinator import UpdateFailed
+
+
+async def test_invalid_credentials(hass, controller, smarttub_api, config_entry):
+    """Check that we return False if the configured credentials are invalid.
+
+    This should mean that the user changed their SmartTub password.
+    """
+
+    smarttub_api.login.side_effect = smarttub.LoginFailed
+    controller = SmartTubController(hass)
+    ret = await controller.async_setup_entry(config_entry)
+    assert ret is False
+
+
+async def test_update(controller, spa):
+    """Test data updates from API."""
+    data = await controller.async_update_data()
+    assert data[spa.id] == {"status": spa.get_status.return_value}
+
+    spa.get_status.side_effect = smarttub.APIError
+    with pytest.raises(UpdateFailed):
+        data = await controller.async_update_data()
+
+
+async def test_login(controller, smarttub_api, account):
+    """Test SmartTubController.login."""
+    smarttub_api.get_account.return_value.id = "account-id1"
+    account = await controller.login("test-email1", "test-password1")
+    smarttub_api.login.assert_called()
+    assert account == account
diff --git a/tests/components/smarttub/test_entity.py b/tests/components/smarttub/test_entity.py
new file mode 100644
index 00000000000..4a19b265090
--- /dev/null
+++ b/tests/components/smarttub/test_entity.py
@@ -0,0 +1,18 @@
+"""Test SmartTubEntity."""
+
+from homeassistant.components.smarttub.entity import SmartTubEntity
+
+
+async def test_entity(coordinator, spa):
+    """Test SmartTubEntity."""
+
+    entity = SmartTubEntity(coordinator, spa, "entity1")
+
+    assert entity.device_info
+    assert entity.name
+
+    coordinator.data[spa.id] = {}
+    assert entity.get_spa_status("foo") is None
+    coordinator.data[spa.id]["status"] = {"foo": "foo1", "bar": {"baz": "barbaz1"}}
+    assert entity.get_spa_status("foo") == "foo1"
+    assert entity.get_spa_status("bar.baz") == "barbaz1"
diff --git a/tests/components/smarttub/test_init.py b/tests/components/smarttub/test_init.py
new file mode 100644
index 00000000000..aa22780e9b8
--- /dev/null
+++ b/tests/components/smarttub/test_init.py
@@ -0,0 +1,60 @@
+"""Test smarttub setup process."""
+
+import asyncio
+from unittest.mock import patch
+
+import pytest
+from smarttub import LoginFailed
+
+from homeassistant.components import smarttub
+from homeassistant.exceptions import ConfigEntryNotReady
+from homeassistant.setup import async_setup_component
+
+
+async def test_setup_with_no_config(hass):
+    """Test that we do not discover anything."""
+    assert await async_setup_component(hass, smarttub.DOMAIN, {}) is True
+
+    # No flows started
+    assert len(hass.config_entries.flow.async_progress()) == 0
+
+    assert smarttub.const.SMARTTUB_CONTROLLER not in hass.data[smarttub.DOMAIN]
+
+
+async def test_setup_entry_not_ready(hass, config_entry, smarttub_api):
+    """Test setup when the entry is not ready."""
+    assert await async_setup_component(hass, smarttub.DOMAIN, {}) is True
+    smarttub_api.login.side_effect = asyncio.TimeoutError
+
+    with pytest.raises(ConfigEntryNotReady):
+        await smarttub.async_setup_entry(hass, config_entry)
+
+
+async def test_setup_auth_failed(hass, config_entry, smarttub_api):
+    """Test setup when the credentials are invalid."""
+    assert await async_setup_component(hass, smarttub.DOMAIN, {}) is True
+    smarttub_api.login.side_effect = LoginFailed
+
+    assert await smarttub.async_setup_entry(hass, config_entry) is False
+
+
+async def test_config_passed_to_config_entry(hass, config_entry, config_data):
+    """Test that configured options are loaded via config entry."""
+    config_entry.add_to_hass(hass)
+    ret = await async_setup_component(hass, smarttub.DOMAIN, config_data)
+    assert ret is True
+
+
+async def test_unload_entry(hass, config_entry, smarttub_api):
+    """Test being able to unload an entry."""
+    config_entry.add_to_hass(hass)
+
+    assert await async_setup_component(hass, smarttub.DOMAIN, {}) is True
+
+    assert await smarttub.async_unload_entry(hass, config_entry)
+
+    # test failure of platform unload
+    assert await async_setup_component(hass, smarttub.DOMAIN, {}) is True
+    with patch.object(hass.config_entries, "async_forward_entry_unload") as mock:
+        mock.return_value = False
+        assert await smarttub.async_unload_entry(hass, config_entry) is False