diff --git a/CHANGELOG.md b/CHANGELOG.md
index 24d85ea9..3e5c948d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -23,6 +23,7 @@ and start a new "In Progress" section above it.
 
 - Include `job_options` as top-level properties in `GET /jobs/{job_id}` response ([#470](https://github.com/Open-EO/openeo-python-driver/issues/470))
 - Bump STAC version from `0.9.0` to `1.0.0` in capabilities endpoint, collection metadata, job results and ML model metadata ([#363](https://github.com/Open-EO/openeo-python-driver/issues/363))
+- `load_collection`: add check on malformed `spatial_extent`. ([#284](https://github.com/Open-EO/openeo-python-driver/issues/284))
 
 
 ## 0.139.0
diff --git a/openeo_driver/processgraph/process_implementations/io.py b/openeo_driver/processgraph/process_implementations/io.py
index 82092f3a..66756704 100644
--- a/openeo_driver/processgraph/process_implementations/io.py
+++ b/openeo_driver/processgraph/process_implementations/io.py
@@ -61,7 +61,7 @@ def _extract_temporal_extent(args: ProcessArgs, field="extent", process_id="filt
 
 
 def _extract_bbox_extent(args: ProcessArgs, field="extent", process_id="filter_bbox", handle_geojson=False) -> dict:
-    extent = args.get_required(name=field)
+    extent = args.get_required(name=field, expected_type=dict)
     if handle_geojson and extent.get("type") in [
         "Polygon", "MultiPolygon", "GeometryCollection", "Feature", "FeatureCollection",
     ]:
@@ -79,8 +79,44 @@ def _extract_bbox_extent(args: ProcessArgs, field="extent", process_id="filter_b
             )
         d = {"west": w, "south": s, "east": e, "north": n, "crs": "EPSG:4326"}
     elif all(k in extent for k in ["west", "south", "east", "north"]):
-        d = {k: extent[k] for k in ["west", "south", "east", "north"]}
-        crs = extent.get("crs") or "EPSG:4326"
+        d = {}
+        for key in ["west", "south", "east", "north"]:
+            value = extent[key]
+            if isinstance(value, bool) or not isinstance(value, (int, float)):
+                raise ProcessParameterInvalidException(
+                    parameter=field,
+                    process=process_id,
+                    reason=f"'{key}' must be a number, but got {value!r}.",
+                )
+            d[key] = value
+
+        if d["west"] >= d["east"]:
+            raise ProcessParameterInvalidException(
+                parameter=field,
+                process=process_id,
+                reason=f"'west' must be smaller than 'east', but got west={d['west']!r} and east={d['east']!r}.",
+            )
+        if d["south"] >= d["north"]:
+            raise ProcessParameterInvalidException(
+                parameter=field,
+                process=process_id,
+                reason=f"'south' must be smaller than 'north', but got south={d['south']!r} and north={d['north']!r}.",
+            )
+
+        crs = extent.get("crs")
+        if crs is None and (
+            d["west"] < -360 or d["west"] > 360 or d["east"] < -360 or d["east"] > 360
+            or d["south"] < -100 or d["south"] > 100 or d["north"] < -100 or d["north"] > 100
+        ):
+            raise ProcessParameterInvalidException(
+                parameter=field,
+                process=process_id,
+                reason=(
+                    "coordinates are outside the valid EPSG:4326 range while no 'crs' was specified. "
+                    "Specify the correct 'crs' explicitly."
+                ),
+            )
+        crs = crs or "EPSG:4326"
         if isinstance(crs, int):
             crs = "EPSG:{crs}".format(crs=crs)
         d["crs"] = crs
diff --git a/tests/test_views_validation.py b/tests/test_views_validation.py
index a0000f91..46e4c354 100644
--- a/tests/test_views_validation.py
+++ b/tests/test_views_validation.py
@@ -49,3 +49,65 @@ def test_load_collection_basic(api100, backend_implementation):
     res = api100.validation(pg)
     errors = res.json["errors"]
     assert errors == [{"code": "MissingProduct", "message": "Tile 4322 not available"}]
+
+
+@pytest.mark.parametrize(
+    ["spatial_extent", "expected_message_part"],
+    [
+        ([1, 2, 3, 4], "Expected dictionary/mapping but got"),
+        (
+            {"west": [0], "south": 60.11, "east": 25.24, "north": 60.35},
+            "'west' must be a number, but got [0].",
+        ),
+        (
+            {"west": 5, "south": 51.215, "east": 4, "north": 51.22},
+            "'west' must be smaller than 'east'",
+        ),
+        (
+            {"west": 4, "south": 51.22, "east": 5, "north": 51.215},
+            "'south' must be smaller than 'north'",
+        ),
+        (
+            {
+                "west": 4329317.717132108,
+                "east": 4330615.2810456185,
+                "north": 3005295.0854642093,
+                "south": 3003997.791438847,
+            },
+            "outside the valid EPSG:4326 range while no 'crs' was specified",
+        ),
+    ],
+)
+def test_validation_load_collection_invalid_spatial_extent(api100, spatial_extent, expected_message_part):
+    pg = {
+        "lc": {
+            "process_id": "load_collection",
+            "arguments": {"id": "S2_FOOBAR", "spatial_extent": spatial_extent},
+            "result": True,
+        }
+    }
+    res = api100.validation(pg)
+    errors = res.json["errors"]
+    assert len(errors) == 1
+    assert errors[0]["code"] == "ProcessParameterInvalid"
+    assert expected_message_part in errors[0]["message"]
+
+
+@pytest.mark.parametrize(
+    "spatial_extent",
+    [
+        {"west": -200, "south": 51.215, "east": -190, "north": 51.22},
+        {"west": 4, "south": 95, "east": 5, "north": 96},
+    ],
+)
+def test_validation_load_collection_spatial_extent_lenient_epsg4326_default_bounds(api100, spatial_extent):
+    pg = {
+        "lc": {
+            "process_id": "load_collection",
+            "arguments": {"id": "S2_FOOBAR", "spatial_extent": spatial_extent},
+            "result": True,
+        }
+    }
+    res = api100.validation(pg)
+    errors = res.json["errors"]
+    assert all(error["code"] != "ProcessParameterInvalid" for error in errors)