In Barbie Mermaid Adventure, Barbie assumes the role of a specimen of that mythical fish-human hybrid, the mermaid, and plans a party with all of her undersea friends. Unfortunately, a magical light shell in the main palace broke. In order to fix it, Barbie needs to enlist the help of 3 rainbow dolphins.

Explore three exotic undersea worlds!; Play seven fun-filled games and activities!; Care for cuddlefish, free Whisper the whale, and more!; Collect decorations and hand out party invitations!; Help Mermaid Barbie and her friends compose the "Song of the Sea"!; Play two of a kind with school fish and watch them dance at the celebration and design a crown and necklace for Barbie to wear!