diff --git a/elasticapm/traces.py b/elasticapm/traces.py
index 583505070..929458d7a 100644
--- a/elasticapm/traces.py
+++ b/elasticapm/traces.py
@@ -531,7 +531,7 @@ def __init__(
         span_subtype: Optional[str] = None,
         span_action: Optional[str] = None,
         sync: Optional[bool] = None,
-        start: Optional[int] = None,
+        start: Optional[float] = None,
         links: Optional[Sequence[TraceParent]] = None,
     ) -> None:
         """
@@ -1044,7 +1044,7 @@ def __init__(
         labels: Optional[dict] = None,
         span_subtype: Optional[str] = None,
         span_action: Optional[str] = None,
-        start: Optional[int] = None,
+        start: Optional[float] = None,
         duration: Optional[Union[float, timedelta]] = None,
         sync: Optional[bool] = None,
         links: Optional[Sequence[TraceParent]] = None,