diff --git a/tests/test_core.py b/tests/test_core.py
index b46da656..0c29b246 100644
--- a/tests/test_core.py
+++ b/tests/test_core.py
@@ -3,7 +3,6 @@
 import decimal
 import json
 
-import pendulum
 import pytest
 import sqlalchemy as sa
 from faker import Faker
@@ -28,12 +27,12 @@
 )
 
 SAMPLE_CONFIG = {
-    "start_date": pendulum.datetime(2022, 11, 1).to_iso8601_string(),
+    "start_date": datetime.datetime(2022, 11, 1).isoformat(),
     "sqlalchemy_url": DB_SQLALCHEMY_URL,
 }
 
 NO_SQLALCHEMY_CONFIG = {
-    "start_date": pendulum.datetime(2022, 11, 1).to_iso8601_string(),
+    "start_date": datetime.datetime(2022, 11, 1).isoformat(),
     "host": "localhost",
     "port": 5432,
     "user": "postgres",
diff --git a/tests/test_replication_key.py b/tests/test_replication_key.py
index 7f46f3bf..eb0efd1f 100644
--- a/tests/test_replication_key.py
+++ b/tests/test_replication_key.py
@@ -1,9 +1,9 @@
 """Tests standard tap features using the built-in SDK tests library."""
 
 import copy
+import datetime
 import json
 
-import pendulum
 import sqlalchemy as sa
 from singer_sdk.testing.runners import TapTestRunner
 from singer_sdk.testing.templates import TapTestTemplate
@@ -14,7 +14,7 @@
 
 TABLE_NAME = "test_replication_key"
 SAMPLE_CONFIG = {
-    "start_date": pendulum.datetime(2022, 11, 1).to_iso8601_string(),
+    "start_date": datetime.datetime(2022, 11, 1).isoformat(),
     "sqlalchemy_url": DB_SQLALCHEMY_URL,
 }
 
@@ -68,11 +68,11 @@ def test_null_replication_key_with_start_date():
         table.drop(conn, checkfirst=True)
         metadata_obj.create_all(conn)
         insert = table.insert().values(
-            data="Alpha", updated_at=pendulum.datetime(2022, 10, 20).to_iso8601_string()
+            data="Alpha", updated_at=datetime.datetime(2022, 10, 20).isoformat()
         )
         conn.execute(insert)
         insert = table.insert().values(
-            data="Bravo", updated_at=pendulum.datetime(2022, 11, 20).to_iso8601_string()
+            data="Bravo", updated_at=datetime.datetime(2022, 11, 20).isoformat()
         )
         conn.execute(insert)
         insert = table.insert().values(data="Zulu", updated_at=None)
@@ -124,11 +124,11 @@ def test_null_replication_key_without_start_date():
         table.drop(conn, checkfirst=True)
         metadata_obj.create_all(conn)
         insert = table.insert().values(
-            data="Alpha", updated_at=pendulum.datetime(2022, 10, 20).to_iso8601_string()
+            data="Alpha", updated_at=datetime.datetime(2022, 10, 20).isoformat()
         )
         conn.execute(insert)
         insert = table.insert().values(
-            data="Bravo", updated_at=pendulum.datetime(2022, 11, 20).to_iso8601_string()
+            data="Bravo", updated_at=datetime.datetime(2022, 11, 20).isoformat()
         )
         conn.execute(insert)
         insert = table.insert().values(data="Zulu", updated_at=None)