diff --git a/observatory_platform/date_utils.py b/observatory_platform/date_utils.py
new file mode 100644
index 000000000..bc55df23b
--- /dev/null
+++ b/observatory_platform/date_utils.py
@@ -0,0 +1,37 @@
+# Copyright 2024 Curtin University
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Author: Keegan Smith
+
+from datetime import datetime
+from typing import Union
+from zoneinfo import ZoneInfo
+
+from dateutil import parser
+
+
+def datetime_normalise(dt: Union[str, datetime]) -> str:
+    """
+    Converts a datetime object or string to an isoformatted datetime string at +0000UTC
+
+    :param dt_string:  The string to convert
+    :return: The ISO formatted datetime string
+    """
+    if isinstance(dt, str):
+        dt = parser.parse(dt)  # Parse string to datetime object
+    if not dt.utcoffset():  # If no timezone present, assume +0000UTC
+        dt = dt.replace(tzinfo=ZoneInfo("UTC"))
+    dt = dt.astimezone(ZoneInfo("UTC"))
+
+    return dt.isoformat()
diff --git a/observatory_platform/tests/test_date_utils.py b/observatory_platform/tests/test_date_utils.py
new file mode 100644
index 000000000..c8640b0f9
--- /dev/null
+++ b/observatory_platform/tests/test_date_utils.py
@@ -0,0 +1,68 @@
+# Copyright 2024 Curtin University
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Author: Keegan Smith
+
+from datetime import datetime
+import unittest
+from zoneinfo import ZoneInfo
+
+from observatory_platform.date_utils import datetime_normalise
+
+
+class test_normalise_datetime(unittest.TestCase):
+    """Tests for normalise_datetime"""
+
+    def test_str_inputs(self):
+        inputs = [
+            "2024-01-01 12:00:00+0000",
+            "2024-01-01 00:00:00+0800",
+            "2024-01-01 12:00:00-0800",
+            "2024-01-01 12:00:00Z",
+            "2024-01-01 12:00:00UTC+1",
+        ]
+        expected_outputs = [
+            "2024-01-01T12:00:00+00:00",
+            "2023-12-31T16:00:00+00:00",
+            "2024-01-01T20:00:00+00:00",
+            "2024-01-01T12:00:00+00:00",
+            "2024-01-01T13:00:00+00:00",
+        ]
+        for input, expected_output in zip(inputs, expected_outputs):
+            actual_output = datetime_normalise(input)
+            self.assertEqual(expected_output, actual_output)
+
+    def test_dt_inputs(self):
+        inputs = [
+            datetime(2024, 1, 1, 12, 0, 0, tzinfo=ZoneInfo("UTC")),
+            datetime(2024, 1, 1, 12, 0, 0, tzinfo=ZoneInfo("Etc/GMT+1")),
+            datetime(2024, 1, 1, 0, 0, 0, tzinfo=ZoneInfo("Etc/GMT-1")),
+            datetime(2023, 12, 31, 23, 0, 0, tzinfo=ZoneInfo("Etc/GMT+1")),
+        ]
+        expected_outputs = [
+            "2024-01-01T12:00:00+00:00",
+            "2024-01-01T13:00:00+00:00",
+            "2023-12-31T23:00:00+00:00",
+            "2024-01-01T00:00:00+00:00",
+        ]
+        for input, expected_output in zip(inputs, expected_outputs):
+            actual_output = datetime_normalise(input)
+            self.assertEqual(expected_output, actual_output)
+
+    def test_missing_tz(self):
+        inputs = ["2024-01-01 00:00:00", "2024-01-01T12:00:00", datetime(2024, 1, 1, 12, 0, 0)]
+        expected_outputs = ["2024-01-01T00:00:00+00:00", "2024-01-01T12:00:00+00:00", "2024-01-01T12:00:00+00:00"]
+        for input, expected_output in zip(inputs, expected_outputs):
+            actual_output = datetime_normalise(input)
+            self.assertEqual(expected_output, actual_output)
diff --git a/pyproject.toml b/pyproject.toml
index 1d108b354..ac53f14b0 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -53,6 +53,7 @@ dependencies = [
     "validators<=0.20.0",
     "xmltodict",
     "tenacity",
+    "python-dateutil",
 ]
 
 [project.optional-dependencies]