diff --git a/regularizepsf/psf.py b/regularizepsf/psf.py
index 9ad9fe4..70a9ed4 100644
--- a/regularizepsf/psf.py
+++ b/regularizepsf/psf.py
@@ -3,6 +3,7 @@
 from __future__ import annotations
 
 import inspect
+import pathlib
 from typing import TYPE_CHECKING, Any, cast
 from functools import partial
 
@@ -17,7 +18,6 @@
 from regularizepsf.visualize import KERNEL_IMSHOW_ARGS_DEFAULT, PSF_IMSHOW_ARGS_DEFAULT, visualize_grid
 
 if TYPE_CHECKING:
-    import pathlib
     from numbers import Real
     from collections.abc import Callable
 
@@ -272,6 +272,7 @@ def save(self, path: pathlib.Path) -> None:
         None
 
         """
+        path = pathlib.Path(path)
         if path.suffix == ".h5":
             with h5py.File(path, "w") as f:
                 f.create_dataset("coordinates", data=self.coordinates)
@@ -302,6 +303,7 @@ def load(cls, path: pathlib.Path) -> ArrayPSF:
             loaded model
 
         """
+        path = pathlib.Path(path)
         if path.suffix == ".h5":
             with h5py.File(path, "r") as f:
                 coordinates = [tuple(c) for c in f["coordinates"][:]]
diff --git a/regularizepsf/transform.py b/regularizepsf/transform.py
index 7107522..4d70a6f 100644
--- a/regularizepsf/transform.py
+++ b/regularizepsf/transform.py
@@ -2,6 +2,7 @@
 
 from __future__ import annotations
 
+import pathlib
 from typing import TYPE_CHECKING
 
 import h5py
@@ -15,7 +16,6 @@
 from regularizepsf.visualize import KERNEL_IMSHOW_ARGS_DEFAULT, visualize_grid
 
 if TYPE_CHECKING:
-    import pathlib
 
     from regularizepsf.psf import ArrayPSF
 
@@ -173,6 +173,7 @@ def save(self, path: pathlib.Path) -> None:
         None
 
         """
+        path = pathlib.Path(path)
         if path.suffix == ".h5":
             with h5py.File(path, "w") as f:
                 f.create_dataset("coordinates", data=self.coordinates)
@@ -201,6 +202,7 @@ def load(cls, path: pathlib.Path) -> ArrayPSFTransform:
         PSFTransform
 
         """
+        path = pathlib.Path(path)
         if path.suffix == ".h5":
             with h5py.File(path, "r") as f:
                 coordinates = [tuple(c) for c in f["coordinates"][:]]