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Legendary Island (Japanese: でんせつのことう Legendary Solitary Island) is a Friend Area in Pokémon Mystery Dungeon: Red Rescue Team and Blue Rescue Team that is obtained when recruiting either Articuno, Zapdos, or Moltres. It is the only Friend Area in the Northern Isles area and has a capacity of three Pokémon. The island seems to be a reference to the three islands in the second movie.
After recruiting all three legendary birds, talking to Alakazam, and visiting this Friend Area, Lugia's dungeon, Silver Trench, is unlocked.
Legendary Island is split into three smaller islands representing Articuno, Zapdos, and Moltres. All three islands are connected by a bridge. Moltres's island is represented with a volcano, Articuno's with a mountain covered with snow, and Zapdos's with a simple field. Each island has what appears to be a small temple on it, which are very similar to those used to store the spheres in The Power of One.