diff --git a/Sensor/adr_sensor/utils/timestamp_utils.py b/Sensor/adr_sensor/utils/timestamp_utils.py
index d7263b59..e7b406d9 100644
--- a/Sensor/adr_sensor/utils/timestamp_utils.py
+++ b/Sensor/adr_sensor/utils/timestamp_utils.py
@@ -2,9 +2,18 @@
 Timestamp utilities for standardized datetime handling across parsers.
 """
 
+import re
 from datetime import datetime, timezone
 from typing import Optional, Union
 
+# Python < 3.11 fromisoformat() only accepts 3 or 6 fractional-second digits,
+# but RFC 3339 writers (e.g. Go's RFC3339Nano) emit anywhere from 1 to 9.
+_FRACTIONAL_SECONDS = re.compile(r"(?<=:\d\d)\.(\d+)")
+
+
+def _fraction_to_microseconds(match: "re.Match[str]") -> str:
+    return "." + (match.group(1) + "000000")[:6]
+
 
 def normalize_timestamp(timestamp: Union[str, int, float, datetime]) -> datetime:
     """Convert any timestamp format to a timezone-aware datetime in UTC.
@@ -28,6 +37,7 @@ def normalize_timestamp(timestamp: Union[str, int, float, datetime]) -> datetime
     elif isinstance(timestamp, str):
         try:
             iso_str = timestamp.replace("Z", "+00:00")
+            iso_str = _FRACTIONAL_SECONDS.sub(_fraction_to_microseconds, iso_str, count=1)
             dt = datetime.fromisoformat(iso_str)
         except ValueError:
             try:
diff --git a/Sensor/tests/test_utils.py b/Sensor/tests/test_utils.py
index c14c69c5..143e19ef 100644
--- a/Sensor/tests/test_utils.py
+++ b/Sensor/tests/test_utils.py
@@ -91,6 +91,22 @@ def test_float_timestamp(self):
         dt = normalize_timestamp(1704067200.5)
         assert dt.year == 2024
 
+    @pytest.mark.parametrize(
+        ("value", "microsecond"),
+        [
+            ("2025-07-16T13:32:09.5Z", 500000),
+            ("2025-07-16T13:32:09.12345Z", 123450),
+            ("2025-07-16T13:32:09.123456789Z", 123456),
+            ("2025-07-16T13:32:09.123456789-07:00", 123456),
+            ("2025-07-16 13:32:09.1234567", 123456),
+        ],
+    )
+    def test_iso_string_with_any_fraction_length(self, value, microsecond):
+        # Python < 3.11 fromisoformat() only accepts 3 or 6 fractional digits.
+        dt = normalize_timestamp(value)
+        assert dt.tzinfo == timezone.utc
+        assert (dt.minute, dt.second, dt.microsecond) == (32, 9, microsecond)
+
 
 class TestFormatTimestampForFilename:
     def test_format(self):