What was the title of the first Pokémon video game released outside Japan in the main series?

Pokémon Red and Blue was the first main-series Pokémon game release outside Japan.

The original Japanese games were Pocket Monsters Red and Green, released for the Game Boy in 1996. Nintendo later used the enhanced Japanese Blue version as the basis for the international Red and Blue releases, which launched in North America in 1998 and in other regions afterward.

The international pair introduced players to the Kanto region, the original 151 Pokémon, and the series’ central activities: capturing, training, battling, and trading. The two versions contained version-exclusive Pokémon, encouraging players to connect and trade.

Pokémon Yellow followed as an enhanced release inspired by the anime, with Pikachu accompanying the player. The Japanese Green version was not released internationally under that title, which is why Red and Blue became the familiar first entries for many players worldwide.