Monster High: Escape from Skull Shores (2012)

It's officially Spring Break at Monster High, and Lagoona takes her gilfriends across the sea to the Great Barrier Reef, but they are ship wrecked and end up on a mysterious skull shaped island. Here they enjoy the local hospitality until they realize that they are being used by a slippery showman named Farnum to lure the rarest, most mysterious monster of them all, "the Beast" into a trap. Frankie is taken by the Beast but tables turn and she ends up rescuing him and returning with him to Monster High. The story goes to high voltage when they realize that Frankie has inadvertently led Farnum to the location of the greatest gathering of monsters anywhere...Monster High.

Source: TMDb