diff --git a/CHANGELOG.md b/CHANGELOG.md
index b9df3154a..d77e837f4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+- Add support in `VectoCube.download()` to guess output format from extension of a given filename
+  ([#401](https://github.com/Open-EO/openeo-python-client/issues/401), [#449](https://github.com/Open-EO/openeo-python-client/issues/449))
+
 ### Changed
 
 ### Removed
diff --git a/openeo/rest/datacube.py b/openeo/rest/datacube.py
index 1c471e68d..6d46bcd37 100644
--- a/openeo/rest/datacube.py
+++ b/openeo/rest/datacube.py
@@ -1943,6 +1943,7 @@ def download(
         :return: None if the result is stored to disk, or a bytes object returned by the backend.
         """
         if format is None and outputfile is not None:
+            # TODO #401/#449 don't guess/override format if there is already a save_result with format?
             format = guess_format(outputfile)
         cube = self._ensure_save_result(format=format, options=options)
         return self._connection.download(cube.flat_graph(), outputfile)
@@ -2062,6 +2063,7 @@ def execute_batch(
         if "format" in format_options and not out_format:
             out_format = format_options["format"]  # align with 'download' call arg name
         if not out_format and outputfile:
+            # TODO #401/#449 don't guess/override format if there is already a save_result with format?
             out_format = guess_format(outputfile)
 
         job = self.create_job(
diff --git a/openeo/rest/vectorcube.py b/openeo/rest/vectorcube.py
index 3715b7a31..57e33342b 100644
--- a/openeo/rest/vectorcube.py
+++ b/openeo/rest/vectorcube.py
@@ -9,7 +9,7 @@
 from openeo.rest._datacube import _ProcessGraphAbstraction, UDF
 from openeo.rest.mlmodel import MlModel
 from openeo.rest.job import BatchJob
-from openeo.util import dict_no_none
+from openeo.util import dict_no_none, guess_format
 
 if typing.TYPE_CHECKING:
     # Imports for type checking only (circular import issue at runtime).
@@ -137,8 +137,10 @@ def execute(self) -> dict:
         return self._connection.execute(self.flat_graph())
 
     def download(self, outputfile: Union[str, pathlib.Path], format: Optional[str] = None, options: dict = None):
-        # TODO #401 guess format from outputfile?
         # TODO #401 make outputfile optional (See DataCube.download)
+        # TODO #401/#449 don't guess/override format if there is already a save_result with format?
+        if format is None and outputfile is not None:
+            format = guess_format(outputfile)
         cube = self._ensure_save_result(format=format, options=options)
         return self._connection.download(cube.flat_graph(), outputfile)
 
diff --git a/openeo/util.py b/openeo/util.py
index ada423bbf..db7cba2da 100644
--- a/openeo/util.py
+++ b/openeo/util.py
@@ -451,6 +451,7 @@ def guess_format(filename: Union[str, Path]) -> str:
     format_map = {
         "gtiff": "GTiff", "geotiff": "GTiff", "geotif": "GTiff", "tiff": "GTiff", "tif": "GTiff",
         "nc": "netCDF", "netcdf": "netCDF",
+        "geojson": "GeoJSON",
     }
 
     return format_map.get(extension, extension.upper())
diff --git a/tests/rest/datacube/test_vectorcube.py b/tests/rest/datacube/test_vectorcube.py
index 7f7f4d944..77539cca3 100644
--- a/tests/rest/datacube/test_vectorcube.py
+++ b/tests/rest/datacube/test_vectorcube.py
@@ -85,9 +85,9 @@ def test_raster_to_vector(con100):
 @pytest.mark.parametrize(
     ["filename", "expected_format"],
     [
-        ("result.json", "GeoJSON"),  # TODO #401 possible to detect "GeoJSON from ".json" extension?
+        ("result.json", "JSON"),  # TODO possible to allow "GeoJSON" with ".json" extension?
         ("result.geojson", "GeoJSON"),
-        ("result.nc", "GeoJSON"),  # TODO #401 autodetect format from filename
+        ("result.nc", "netCDF"),
     ],
 )
 @pytest.mark.parametrize("path_class", [str, Path])
@@ -118,11 +118,12 @@ def test_download_auto_save_result_only_file(
         ("result.json", "JSON", "JSON"),
         ("result.geojson", "GeoJSON", "GeoJSON"),
         ("result.nc", "netCDF", "netCDF"),
-        # TODO #401 more formats to autodetect?
         ("result.nc", "NETcDf", "NETcDf"),  # TODO #401 normalize format
-        ("result.nc", "inV6l1d!!!", "inV6l1d!!!"),  # TODO #401 this should fail
-        ("result.json", None, "GeoJSON"),  # TODO #401 autodetect format from filename?
-        ("result.nc", None, "GeoJSON"),  # TODO #401 autodetect format from filename
+        ("result.nc", "inV6l1d!!!", "inV6l1d!!!"),  # TODO #401 this should fail?
+        ("result.json", None, "JSON"),
+        ("result.geojson", None, "GeoJSON"),
+        ("result.nc", None, "netCDF"),
+        # TODO #449 more formats to autodetect?
     ],
 )
 def test_download_auto_save_result_with_format(vector_cube, download_spy, tmp_path, filename, format, expected_format):
@@ -164,17 +165,18 @@ def test_download_auto_save_result_with_options(vector_cube, download_spy, tmp_p
 
 
 @pytest.mark.parametrize(
-    ["format", "expected_format"],
+    ["output_file", "format", "expected_format"],
     [
-        (None, "GeoJSON"),
-        ("JSON", "JSON"),
-        ("netCDF", "netCDF"),
+        ("result.geojson", None, "GeoJSON"),
+        ("result.geojson", "GeoJSON", "GeoJSON"),
+        ("result.json", "JSON", "JSON"),
+        ("result.nc", "netCDF", "netCDF"),
     ],
 )
-def test_save_result_and_download(vector_cube, download_spy, tmp_path, format, expected_format):
+def test_save_result_and_download(vector_cube, download_spy, tmp_path, output_file, format, expected_format):
     """e.g. https://github.com/Open-EO/openeo-geopyspark-driver/issues/477"""
     vector_cube = vector_cube.save_result(format=format)
-    output_path = tmp_path / "result.json"
+    output_path = tmp_path / output_file
     vector_cube.download(output_path)
     assert download_spy.only_request == {
         "createvectorcube1": {"process_id": "create_vector_cube", "arguments": {}},