diff --git a/ecl2df/wellcompletiondata.py b/ecl2df/wellcompletiondata.py
index e7d225a04..a58437f73 100644
--- a/ecl2df/wellcompletiondata.py
+++ b/ecl2df/wellcompletiondata.py
@@ -228,7 +228,7 @@ def _df2pyarrow(dframe: pd.DataFrame) -> pyarrow.Table:
         else:
             field_metadata = {}
         if colname == "DATE":
-            dtype = pyarrow.timestamp("ms")
+            dtype = pyarrow.timestamp("ns")
         elif pd.api.types.is_integer_dtype(dframe.dtypes[colname]):
             dtype = pyarrow.int32()
         elif pd.api.types.is_string_dtype(dframe.dtypes[colname]):
diff --git a/tests/test_summary.py b/tests/test_summary.py
index d5f138cbb..e52960750 100644
--- a/tests/test_summary.py
+++ b/tests/test_summary.py
@@ -1118,13 +1118,6 @@ def test_df2pyarrow_500years():
     dframe.index.name = "BOGUS"
     pyat = _df2pyarrow(dframe)
 
-    # pylint: disable=c-extension-no-member
-    with pytest.raises(pyarrow.lib.ArrowInvalid):
-        # We cannot convert this back to Pandas, since it will bail on failing
-        # to use nanosecond timestamps in the dataframe object for these dates.
-        # This is maybe a PyArrow bug/limitation that we must be aware of.
-        pyat.to_pandas()
-
     assert (
         np.array(pyat.column(0))
         == [