diff --git a/freqtrade/data/history/datahandlers/featherdatahandler.py b/freqtrade/data/history/datahandlers/featherdatahandler.py
index ef293d6b2..23d0b2d76 100644
--- a/freqtrade/data/history/datahandlers/featherdatahandler.py
+++ b/freqtrade/data/history/datahandlers/featherdatahandler.py
@@ -1,6 +1,6 @@
 import logging
 
-from pandas import DataFrame, read_feather, to_datetime
+from pandas import DataFrame, read_feather
 from pyarrow import dataset
 
 from freqtrade.configuration import TimeRange
@@ -71,7 +71,7 @@ class FeatherDataHandler(IDataHandler):
                     "volume": "float",
                 }
             )
-            pairdata["date"] = to_datetime(pairdata["date"], unit="ms", utc=True)
+            pairdata["date"] = pairdata["date"].dt.as_unit("ms")
             return pairdata
         except Exception as e:
             logger.exception(
diff --git a/freqtrade/data/history/datahandlers/jsondatahandler.py b/freqtrade/data/history/datahandlers/jsondatahandler.py
index 6e63adc87..a2bd3f6db 100644
--- a/freqtrade/data/history/datahandlers/jsondatahandler.py
+++ b/freqtrade/data/history/datahandlers/jsondatahandler.py
@@ -80,7 +80,7 @@ class JsonDataHandler(IDataHandler):
                 "volume": "float",
             }
         )
-        pairdata["date"] = to_datetime(pairdata["date"], unit="ms", utc=True)
+        pairdata["date"] = to_datetime(pairdata["date"], unit="ms", utc=True).dt.as_unit("ms")
         return pairdata
 
     def ohlcv_append(
diff --git a/freqtrade/data/history/datahandlers/parquetdatahandler.py b/freqtrade/data/history/datahandlers/parquetdatahandler.py
index 1813f9991..7a5cb39f1 100644
--- a/freqtrade/data/history/datahandlers/parquetdatahandler.py
+++ b/freqtrade/data/history/datahandlers/parquetdatahandler.py
@@ -1,6 +1,6 @@
 import logging
 
-from pandas import DataFrame, read_parquet, to_datetime
+from pandas import DataFrame, read_parquet
 
 from freqtrade.configuration import TimeRange
 from freqtrade.constants import DEFAULT_DATAFRAME_COLUMNS, DEFAULT_TRADES_COLUMNS
@@ -68,7 +68,7 @@ class ParquetDataHandler(IDataHandler):
                     "volume": "float",
                 }
             )
-            pairdata["date"] = to_datetime(pairdata["date"], unit="ms", utc=True)
+            pairdata["date"] = pairdata["date"].dt.as_unit("ms")
             return pairdata
         except Exception as e:
             logger.exception(
diff --git a/tests/conftest.py b/tests/conftest.py
index 46601ddfb..dc0860466 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -176,20 +176,20 @@ def generate_test_data(
 
     base = np.random.normal(base, 2, size=size)
     if timeframe == "1y":
-        date = pd.date_range(start, periods=size, freq="1YS", tz="UTC")
+        date = pd.date_range(start, periods=size, freq="1YS", tz="UTC", unit="ms")
     elif timeframe == "1M":
-        date = pd.date_range(start, periods=size, freq="1MS", tz="UTC")
+        date = pd.date_range(start, periods=size, freq="1MS", tz="UTC", unit="ms")
     elif timeframe == "3M":
-        date = pd.date_range(start, periods=size, freq="3MS", tz="UTC")
+        date = pd.date_range(start, periods=size, freq="3MS", tz="UTC", unit="ms")
     elif timeframe == "1w" or timeframe == "7d":
-        date = pd.date_range(start, periods=size, freq="1W-MON", tz="UTC")
+        date = pd.date_range(start, periods=size, freq="1W-MON", tz="UTC", unit="ms")
     else:
         tf_mins = timeframe_to_minutes(timeframe)
         if tf_mins >= 1:
-            date = pd.date_range(start, periods=size, freq=f"{tf_mins}min", tz="UTC")
+            date = pd.date_range(start, periods=size, freq=f"{tf_mins}min", tz="UTC", unit="ms")
         else:
             tf_secs = timeframe_to_seconds(timeframe)
-            date = pd.date_range(start, periods=size, freq=f"{tf_secs}s", tz="UTC")
+            date = pd.date_range(start, periods=size, freq=f"{tf_secs}s", tz="UTC", unit="ms")
     df = pd.DataFrame(
         {
             "date": date,