From Bulbapedia, the community-driven Pokémon encyclopedia.
Blue Point Isle (Japanese: 青岩島 Seigan Isle) is an anime-exclusive location in Johto, and the largest island in the Whirl Islands archipelago. Known as the entryway to the Whirl Islands, it is located northeast of Cianwood City. Ancient seamen named it for the large blue rock near Inland City that guided them safely home.
Trainers who specialize in Water-type Pokémon can register for the Whirl Cup on Blue Point Isle.
In the anime
Ash and his friends arrived on Blue Point Isle in Around the Whirlpool, where they met up with Professor Elm and registered for the upcoming Whirl Cup tournament.
The group returned to Blue Point Isle in Takin' it on the Chinchou and took a cable car, hoping to reach Bluefinland and take a ferry to Yellow Rock Isle. Instead, the group found themselves in Blue Lagoon and participated in the township's annual Chinchou Parade. After helping Dayton and his father Daizō escort a group of Chinchou from the mountains to the ocean, Ash and his friends finally left Blue Point Isle for Yellow Rock Isle.
Cities and towns