diff --git a/src/batdetect2/data/annotations/aoef.py b/src/batdetect2/data/annotations/aoef.py
index 88fa001..4e0d5ca 100644
--- a/src/batdetect2/data/annotations/aoef.py
+++ b/src/batdetect2/data/annotations/aoef.py
@@ -93,7 +93,7 @@ class AOEFLoader(AnnotationLoader):
 
     def load(
         self,
-        base_dir: Optional[data.PathLike] = None,
+        base_dir: data.PathLike | None = None,
     ) -> data.AnnotationSet:
         return load_aoef_annotated_dataset(self.config, base_dir=base_dir)
 
diff --git a/src/batdetect2/data/annotations/batdetect2.py b/src/batdetect2/data/annotations/batdetect2.py
index 1659e55..892fd4f 100644
--- a/src/batdetect2/data/annotations/batdetect2.py
+++ b/src/batdetect2/data/annotations/batdetect2.py
@@ -348,7 +348,7 @@ class BatDetect2MergedLoader(AnnotationLoader):
 
     def load(
         self,
-        base_dir: Optional[PathLike] = None,
+        base_dir: PathLike | None = None,
     ) -> data.AnnotationSet:
         return load_batdetect2_merged_annotated_dataset(
             self.config,
@@ -367,7 +367,7 @@ class BatDetect2FilesLoader(AnnotationLoader):
 
     def load(
         self,
-        base_dir: Optional[PathLike] = None,
+        base_dir: PathLike | None = None,
     ) -> data.AnnotationSet:
         return load_batdetect2_files_annotated_dataset(
             self.config,
diff --git a/src/batdetect2/data/annotations/types.py b/src/batdetect2/data/annotations/types.py
index a496d59..d7478d2 100644
--- a/src/batdetect2/data/annotations/types.py
+++ b/src/batdetect2/data/annotations/types.py
@@ -1,5 +1,5 @@
 from pathlib import Path
-from typing import Optional, Protocol
+from typing import Protocol
 
 from soundevent import data
 
@@ -43,5 +43,5 @@ class AnnotatedDataset(BaseConfig):
 class AnnotationLoader(Protocol):
     def load(
         self,
-        base_dir: Optional[data.PathLike] = None,
+        base_dir: data.PathLike | None = None,
     ) -> data.AnnotationSet: ...