diff --git a/tests/samplers/test_batch.py b/tests/samplers/test_batch.py
index 63f65dd3b4a..7818d9316b8 100644
--- a/tests/samplers/test_batch.py
+++ b/tests/samplers/test_batch.py
@@ -54,6 +54,7 @@ def test_iter(self, sampler: CustomBatchGeoSampler) -> None:
     def test_len(self, sampler: CustomBatchGeoSampler) -> None:
         assert len(sampler) == 2
 
+    @pytest.mark.slow
     @pytest.mark.parametrize("num_workers", [0, 1, 2])
     def test_dataloader(self, sampler: CustomBatchGeoSampler, num_workers: int) -> None:
         ds = CustomGeoDataset()
@@ -93,6 +94,7 @@ def test_iter(self, sampler: RandomBatchGeoSampler) -> None:
     def test_len(self, sampler: RandomBatchGeoSampler) -> None:
         assert len(sampler) == sampler.length // sampler.batch_size
 
+    @pytest.mark.slow
     @pytest.mark.parametrize("num_workers", [0, 1, 2])
     def test_dataloader(self, sampler: RandomBatchGeoSampler, num_workers: int) -> None:
         ds = CustomGeoDataset()
diff --git a/tests/samplers/test_single.py b/tests/samplers/test_single.py
index 424d80c096e..b369a4b5d23 100644
--- a/tests/samplers/test_single.py
+++ b/tests/samplers/test_single.py
@@ -53,6 +53,7 @@ def test_iter(self, sampler: CustomGeoSampler) -> None:
     def test_len(self, sampler: CustomGeoSampler) -> None:
         assert len(sampler) == 2
 
+    @pytest.mark.slow
     @pytest.mark.parametrize("num_workers", [0, 1, 2])
     def test_dataloader(self, sampler: CustomGeoSampler, num_workers: int) -> None:
         ds = CustomGeoDataset()
@@ -91,6 +92,7 @@ def test_iter(self, sampler: RandomGeoSampler) -> None:
     def test_len(self, sampler: RandomGeoSampler) -> None:
         assert len(sampler) == sampler.length
 
+    @pytest.mark.slow
     @pytest.mark.parametrize("num_workers", [0, 1, 2])
     def test_dataloader(self, sampler: RandomGeoSampler, num_workers: int) -> None:
         ds = CustomGeoDataset()
@@ -132,6 +134,7 @@ def test_iter(self, sampler: GridGeoSampler) -> None:
                 query.maxt - query.mint, sampler.roi.maxt - sampler.roi.mint
             )
 
+    @pytest.mark.slow
     @pytest.mark.parametrize("num_workers", [0, 1, 2])
     def test_dataloader(self, sampler: GridGeoSampler, num_workers: int) -> None:
         ds = CustomGeoDataset()