diff --git a/b2/_internal/_cli/autocomplete_install.py b/b2/_internal/_cli/autocomplete_install.py
index bce25401..fe51ab5d 100644
--- a/b2/_internal/_cli/autocomplete_install.py
+++ b/b2/_internal/_cli/autocomplete_install.py
@@ -14,6 +14,7 @@
 import logging
 import os
 import re
+import shlex
 import shutil
 import signal
 import subprocess
@@ -189,7 +190,24 @@ def force_enable(self, completion_script: Path) -> None:
 
     def get_script_path(self) -> Path:
         """Get autocomplete script path for the given program, common logic."""
-        return Path("~/.config/fish/completions/").expanduser() / f"{self.prog}.fish"
+        complete_paths = [
+            Path(p) for p in shlex.split(
+                subprocess.run(
+                    [self.shell_exec, '-c', 'echo $fish_complete_path'],
+                    timeout=30,
+                    text=True,
+                    check=True,
+                    capture_output=True
+                ).stdout
+            )
+        ]
+        user_path = Path("~/.config/fish/completions").expanduser()
+        if complete_paths:
+            target_path = user_path if user_path in complete_paths else complete_paths[0]
+        else:
+            logger.warning("$fish_complete_path is empty, falling back to %r", user_path)
+            target_path = user_path
+        return target_path / f"{self.prog}.fish"
 
     def is_enabled(self) -> bool:
         """