diff --git a/digital_land/datatype/date.py b/digital_land/datatype/date.py
index f5758ca5..0e175026 100644
--- a/digital_land/datatype/date.py
+++ b/digital_land/datatype/date.py
@@ -80,11 +80,11 @@ def normalise(self, fieldvalue, issues=None):
                         continue
 
                     int_part = value.split(".", 1)[0].lstrip("+-")
-                    if len(int_part) not in (9, 10, 12, 13):
+                    if len(int_part) not in (9, 10, 11, 12, 13):
                         continue
 
                     timestamp = float(value)
-                    if len(int_part) == 13 or len(int_part) == 12:
+                    if len(int_part) in (11, 12, 13):
                         timestamp /= 1000.0
                     date = datetime.utcfromtimestamp(timestamp)
                     break
diff --git a/tests/unit/datatype/test_date.py b/tests/unit/datatype/test_date.py
index 42eef170..abc49fa4 100644
--- a/tests/unit/datatype/test_date.py
+++ b/tests/unit/datatype/test_date.py
@@ -55,6 +55,11 @@ class TestDateDataType:
             ("946684800", "2000-01-01"),
             ("1715123456", "2024-05-07"),
             ("171512345678", "1975-06-09"),
+            # 11-digit millisecond timestamps
+            ("13392000000", "1970-06-05"),
+            ("-49507200000", "1968-06-07"),
+            ("10000000000", "1970-04-26"),
+            ("99999999999", "1973-03-03"),
             # years
             ("2020", "2020-01-01"),
             ("2020.0", "2020-01-01"),