diff --git a/include/fs/fs.h b/include/fs/fs.h
index 76bf25bd107..044eab552cc 100644
--- a/include/fs/fs.h
+++ b/include/fs/fs.h
@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2016 Intel Corporation.
+ * Copyright (c) 2020 Nordic Semiconductor ASA
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -320,7 +321,8 @@ ssize_t fs_write(struct fs_file_t *zfp, const void *ptr, size_t size);
  * - FS_SEEK_END = from end of file.
  *
  * @retval 0 Success
- * @retval -ERRNO errno code if error.
+ * @retval -ENOTSUP if underlying file system does not support seeking
+ * @retval < 0 negative errno code
  */
 int fs_seek(struct fs_file_t *zfp, off_t offset, int whence);
 
@@ -331,7 +333,9 @@ int fs_seek(struct fs_file_t *zfp, off_t offset, int whence);
  *
  * @param zfp Pointer to the file object
  *
- * @retval position Current position in file
+ * @retval >= 0 position Current position in file
+ * @retval -ENOTSUP if underlying file system does not support seeking
+ * @retval < 0 negative errno code
  * Current revision does not validate the file object.
  */
 off_t fs_tell(struct fs_file_t *zfp);
diff --git a/subsys/fs/fs.c b/subsys/fs/fs.c
index a662fa3d502..65e98e21cfa 100644
--- a/subsys/fs/fs.c
+++ b/subsys/fs/fs.c
@@ -1,6 +1,7 @@
 /*
  * Copyright (c) 2018 Intel Corporation.
  * Copyright (c) 2020 Peter Bigot Consulting, LLC
+ * Copyright (c) 2020 Nordic Semiconductor ASA
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -218,7 +219,7 @@ ssize_t fs_write(struct fs_file_t *zfp, const void *ptr, size_t size)
 
 int fs_seek(struct fs_file_t *zfp, off_t offset, int whence)
 {
-	int rc = -EINVAL;
+	int rc = -ENOTSUP;
 
 	if (zfp->mp == NULL) {
 		return -EBADF;
@@ -236,7 +237,7 @@ int fs_seek(struct fs_file_t *zfp, off_t offset, int whence)
 
 off_t fs_tell(struct fs_file_t *zfp)
 {
-	int rc = -EINVAL;
+	int rc = -ENOTSUP;
 
 	if (zfp->mp == NULL) {
 		return -EBADF;