Rockhopper Island

Rockhopper Island is an island far away from Club Penguin.

(Not So) Elite Penguin Force
In (Not So) Elite Penguin Force, The Party hijacks the Migrator and sails to Rockhopper Island.

Spies Around the World
In Spies Around the World, The Party goes to Rockhopper Island where X's hideout is to defeat him.

In the remake, Rockhopper Island doesn't appear, and its role is filled by Billybob Island.