Which Pokémon game introduced regional forms through the Alolan forms?

Pokémon Sun and Moon introduced regional forms through the Alolan forms. These alternate appearances and typings first appeared in the Generation VII games for Nintendo 3DS, released worldwide in 2016.

Alolan forms reinterpret familiar Pokémon as species adapted to the tropical island region of Alola. Alolan Vulpix and Ninetales become Ice and Ice/Fairy types, while Alolan Raichu becomes Electric/Psychic. Alolan Exeggutor becomes Grass/Dragon and is famous for its dramatically elongated neck.

The idea expanded the franchise’s approach to evolution and habitat. Instead of simply adding a new species, the games showed how an existing Pokémon could develop a different appearance, type, and behavior in another environment. Later games continued the concept with regional forms in Galar, Hisui, and Paldea.

Regional forms are sometimes confused with Mega Evolutions or alternate costumes. They are different: a regional form is a location-linked biological variation, while Mega Evolution is a temporary battle transformation and a costume does not change a Pokémon’s species form.