Fishman Island is the home of the fishmen and merfolk.[2] It serves as an underwater gateway to the New World for those who do not wish to cross over the Red Line above. Though it is literally directly under the main seat of power of the World Government, it was previously under the protection of Whitebeard, and now Big Mam. It is also notoriously difficult to reach, with only 30% of the ships surviving the journey.[3] It is encased in a giant bubble, allowing human visitors to breathe. For World Nobles, it is also one of the few places in the world where their ability to summon a Marine Admiral as they please is not so easy to accomplish.

The entire Fishman Island is ruled under the Ryugu Kingdom, and as such, every landmark befalls in the kingdom.

■Ryugu Palace
■Mermaid Cove
■Coral Hill
■Candy Factory
■Gyoverly Hills
■Gyoncorde Plaza
■Sea Forest (Northeast of Fishman Island)
■Fishman District
■Noah
■Fishman Karate Dojo
■Candy Factory Town (おかし工場の町, Okashi Kōjō no Machi?) (Northwestern part of Fishman Island)
■Fishman's Meeting Hall (魚民文化会館, Gyomin Bunka Kaikan?) (Southwestern part of Fishman Island)
■Marine Shopping Mall (マリンショッピングモール, Marin Shoppingu Mōru?) (Western part of Fishman Island)
■Water Wheel Town (水車の町, Suisha no Machi?) (Northern part of Fishman Island)