diff --git a/homeassistant/components/local_calendar/calendar.py b/homeassistant/components/local_calendar/calendar.py
index 4b6d9444fd8..6cfcaec61d0 100644
--- a/homeassistant/components/local_calendar/calendar.py
+++ b/homeassistant/components/local_calendar/calendar.py
@@ -2,7 +2,7 @@
 
 from __future__ import annotations
 
-from datetime import datetime
+from datetime import date, datetime, timedelta
 import logging
 from typing import Any
 
@@ -186,14 +186,23 @@ def _parse_event(event: dict[str, Any]) -> Event:
 
 def _get_calendar_event(event: Event) -> CalendarEvent:
     """Return a CalendarEvent from an API event."""
+    start: datetime | date
+    end: datetime | date
+    if isinstance(event.start, datetime) and isinstance(event.end, datetime):
+        start = dt_util.as_local(event.start)
+        end = dt_util.as_local(event.end)
+        if (end - start) <= timedelta(seconds=0):
+            end = start + timedelta(minutes=30)
+    else:
+        start = event.start
+        end = event.end
+        if (end - start) <= timedelta(days=0):
+            end = start + timedelta(days=1)
+
     return CalendarEvent(
         summary=event.summary,
-        start=dt_util.as_local(event.start)
-        if isinstance(event.start, datetime)
-        else event.start,
-        end=dt_util.as_local(event.end)
-        if isinstance(event.end, datetime)
-        else event.end,
+        start=start,
+        end=end,
         description=event.description,
         uid=event.uid,
         rrule=event.rrule.as_rrule_str() if event.rrule else None,
diff --git a/tests/components/local_calendar/conftest.py b/tests/components/local_calendar/conftest.py
index b083bbac78a..7dc294087bd 100644
--- a/tests/components/local_calendar/conftest.py
+++ b/tests/components/local_calendar/conftest.py
@@ -26,10 +26,10 @@ TEST_ENTITY = "calendar.light_schedule"
 class FakeStore(LocalCalendarStore):
     """Mock storage implementation."""
 
-    def __init__(self, hass: HomeAssistant, path: Path) -> None:
+    def __init__(self, hass: HomeAssistant, path: Path, ics_content: str) -> None:
         """Initialize FakeStore."""
         super().__init__(hass, path)
-        self._content = ""
+        self._content = ics_content
 
     def _load(self) -> str:
         """Read from calendar storage."""
@@ -40,15 +40,21 @@ class FakeStore(LocalCalendarStore):
         self._content = ics_content
 
 
+@pytest.fixture(name="ics_content", autouse=True)
+def mock_ics_content() -> str:
+    """Fixture to allow tests to set initial ics content for the calendar store."""
+    return ""
+
+
 @pytest.fixture(name="store", autouse=True)
-def mock_store() -> Generator[None, None, None]:
+def mock_store(ics_content: str) -> Generator[None, None, None]:
     """Test cleanup, remove any media storage persisted during the test."""
 
     stores: dict[Path, FakeStore] = {}
 
     def new_store(hass: HomeAssistant, path: Path) -> FakeStore:
         if path not in stores:
-            stores[path] = FakeStore(hass, path)
+            stores[path] = FakeStore(hass, path, ics_content)
         return stores[path]
 
     with patch(
diff --git a/tests/components/local_calendar/test_calendar.py b/tests/components/local_calendar/test_calendar.py
index a2f13ea289d..559a2af38b3 100644
--- a/tests/components/local_calendar/test_calendar.py
+++ b/tests/components/local_calendar/test_calendar.py
@@ -1,6 +1,7 @@
 """Tests for calendar platform of local calendar."""
 
 import datetime
+import textwrap
 
 import pytest
 
@@ -940,3 +941,91 @@ async def test_create_event_service(
             "location": "Test Location",
         }
     ]
+
+
+@pytest.mark.parametrize(
+    "ics_content",
+    [
+        textwrap.dedent(
+            """\
+            BEGIN:VCALENDAR
+            BEGIN:VEVENT
+            SUMMARY:Bastille Day Party
+            DTSTART:19970714
+            DTEND:19970714
+            END:VEVENT
+            END:VCALENDAR
+        """
+        ),
+        textwrap.dedent(
+            """\
+            BEGIN:VCALENDAR
+            BEGIN:VEVENT
+            SUMMARY:Bastille Day Party
+            DTSTART:19970714
+            DTEND:19970710
+            END:VEVENT
+            END:VCALENDAR
+        """
+        ),
+    ],
+    ids=["no_duration", "negative"],
+)
+async def test_invalid_all_day_event(
+    ws_client: ClientFixture,
+    setup_integration: None,
+    get_events: GetEventsFn,
+) -> None:
+    """Test all day events with invalid durations, which are coerced to be valid."""
+    events = await get_events("1997-07-14T00:00:00Z", "1997-07-16T00:00:00Z")
+    assert list(map(event_fields, events)) == [
+        {
+            "summary": "Bastille Day Party",
+            "start": {"date": "1997-07-14"},
+            "end": {"date": "1997-07-15"},
+        }
+    ]
+
+
+@pytest.mark.parametrize(
+    "ics_content",
+    [
+        textwrap.dedent(
+            """\
+            BEGIN:VCALENDAR
+            BEGIN:VEVENT
+            SUMMARY:Bastille Day Party
+            DTSTART:19970714T110000
+            DTEND:19970714T110000
+            END:VEVENT
+            END:VCALENDAR
+        """
+        ),
+        textwrap.dedent(
+            """\
+            BEGIN:VCALENDAR
+            BEGIN:VEVENT
+            SUMMARY:Bastille Day Party
+            DTSTART:19970714T110000
+            DTEND:19970710T100000
+            END:VEVENT
+            END:VCALENDAR
+        """
+        ),
+    ],
+    ids=["no_duration", "negative"],
+)
+async def test_invalid_event_duration(
+    ws_client: ClientFixture,
+    setup_integration: None,
+    get_events: GetEventsFn,
+) -> None:
+    """Test events with invalid durations, which are coerced to be valid."""
+    events = await get_events("1997-07-14T00:00:00Z", "1997-07-16T00:00:00Z")
+    assert list(map(event_fields, events)) == [
+        {
+            "summary": "Bastille Day Party",
+            "start": {"dateTime": "1997-07-14T11:00:00-06:00"},
+            "end": {"dateTime": "1997-07-14T11:30:00-06:00"},
+        }
+    ]