diff --git a/app/models/contact_list.py b/app/models/contact_list.py
index 16ece39e4..870ef80de 100644
--- a/app/models/contact_list.py
+++ b/app/models/contact_list.py
@@ -4,7 +4,6 @@ from os import path
 from flask import abort, current_app
 from notifications_utils.formatters import strip_whitespace
 from notifications_utils.recipients import RecipientCSV
-from notifications_utils.timezones import utc_string_to_aware_gmt_datetime
 from werkzeug.utils import cached_property
 
 from app.models import JSONModel, ModelList
@@ -23,6 +22,7 @@ class ContactList(JSONModel):
 
     ALLOWED_PROPERTIES = {
         'id',
+        'created_at',
         'created_by',
         'has_jobs',
         'recent_job_count',
@@ -115,10 +115,6 @@ class ContactList(JSONModel):
             contact_list_id=self.id,
         )
 
-    @property
-    def created_at(self):
-        return utc_string_to_aware_gmt_datetime(self._dict['created_at'])
-
     @property
     def contents(self):
         return self.download(self.service_id, self.id)
diff --git a/tests/app/main/views/test_send.py b/tests/app/main/views/test_send.py
index 71a1916bf..0b64ae2fd 100644
--- a/tests/app/main/views/test_send.py
+++ b/tests/app/main/views/test_send.py
@@ -4285,7 +4285,7 @@ def test_redirects_to_template_if_job_exists_already(
         '123 phone numbers',
     ),
 ))
-@freeze_time('2020-03-13 13:00')
+@freeze_time('2020-06-13 13:00')
 def test_choose_from_contact_list(
     mocker,
     client_request,
diff --git a/tests/app/main/views/uploads/test_upload_contact_list.py b/tests/app/main/views/uploads/test_upload_contact_list.py
index 9f0b98ce1..96c0d3f37 100644
--- a/tests/app/main/views/uploads/test_upload_contact_list.py
+++ b/tests/app/main/views/uploads/test_upload_contact_list.py
@@ -458,7 +458,7 @@ def test_cant_save_bad_contact_list(
     (False, 'Not used yet.'),
     (True, 'Not used in the last 7 days.'),
 ])
-@freeze_time('2020-03-13 16:51:56')
+@freeze_time('2020-06-13 16:51:56')
 def test_view_contact_list(
     mocker,
     client_request,
diff --git a/tests/app/models/test_contact_list.py b/tests/app/models/test_contact_list.py
index 9e6e32cd0..6877883b1 100644
--- a/tests/app/models/test_contact_list.py
+++ b/tests/app/models/test_contact_list.py
@@ -1,15 +1,7 @@
-from datetime import datetime
-
 from app.models.contact_list import ContactList
 from app.models.job import PaginatedJobs
 
 
-def test_created_at():
-    created_at = ContactList({'created_at': '2016-05-06T07:08:09.061258'}).created_at
-    assert isinstance(created_at, datetime)
-    assert created_at.isoformat() == '2016-05-06T08:08:09.061258+01:00'
-
-
 def test_get_jobs(mock_get_jobs):
     contact_list = ContactList({'id': 'a', 'service_id': 'b'})
     assert isinstance(contact_list.get_jobs(page=123), PaginatedJobs)
diff --git a/tests/conftest.py b/tests/conftest.py
index 64782fdd6..7b9cf9159 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -1852,7 +1852,7 @@ def mock_create_contact_list(mocker, api_user_active):
 def mock_get_contact_lists(mocker, api_user_active, fake_uuid):
     def _get(service_id, template_type=None):
         return [{
-            'created_at': '2020-03-13 10:59:56',
+            'created_at': '2020-06-13T09:59:56.000000Z',
             'created_by': 'Test User',
             'id': fake_uuid,
             'original_file_name': 'EmergencyContactList.xls',
@@ -1862,7 +1862,7 @@ def mock_get_contact_lists(mocker, api_user_active, fake_uuid):
             'service_id': service_id,
             'template_type': 'email',
         }, {
-            'created_at': '2020-03-13 13:00:00',
+            'created_at': '2020-06-13T12:00:00.000000Z',
             'created_by': 'Test User',
             'id': 'd7b0bd1a-d1c7-4621-be5c-3c1b4278a2ad',
             'original_file_name': 'phone number list.csv',
@@ -1872,7 +1872,7 @@ def mock_get_contact_lists(mocker, api_user_active, fake_uuid):
             'service_id': service_id,
             'template_type': 'sms',
         }, {
-            'created_at': '2020-02-02 02:00:00',
+            'created_at': '2020-05-02T01:00:00.000000Z',
             'created_by': 'Test User',
             'id': fake_uuid,
             'original_file_name': 'UnusedList.tsv',
@@ -1893,7 +1893,7 @@ def mock_get_contact_lists(mocker, api_user_active, fake_uuid):
 def mock_get_contact_list(mocker, api_user_active, fake_uuid):
     def _get(*, service_id, contact_list_id):
         return {
-            'created_at': '2020-03-13 10:59:56',
+            'created_at': '2020-06-13T09:59:56.000000Z',
             'created_by': 'Test User',
             'id': fake_uuid,
             'original_file_name': 'EmergencyContactList.xls',