diff --git a/src/poetry_plugin_shell/command.py b/src/poetry_plugin_shell/command.py
index 234ac85..aa751c4 100644
--- a/src/poetry_plugin_shell/command.py
+++ b/src/poetry_plugin_shell/command.py
@@ -34,6 +34,14 @@ def handle(self) -> int:
                 f"Virtual environment already activated: <info>{self.env.path}</>"
             )
 
+            # Only activate if not already inside a Poetry-spawned shell (avoid nesting).
+            if os.environ.get("POETRY_ACTIVE") == "1":
+                env = self.env
+                assert env.is_venv()
+                env = cast("VirtualEnv", env)
+                shell = Shell.get()
+                shell.activate(env)
+
             return 0
 
         self.line(f"Spawning shell within <info>{self.env.path}</>")