Which Pokémon title was the first Stadium game released outside Japan?

Pokémon Stadium was the first Stadium game released outside Japan.

The Nintendo 64 title followed the Japan-only Pocket Monsters Stadium, which had been released in 1998 and allowed battles with only 40 Pokémon. The international Pokémon Stadium was released in Japan in 1999 and then reached Australia, Europe, and North America in 2000.

Unlike its predecessor, Pokémon Stadium supported all 151 first-generation Pokémon in its battle system. With the bundled Transfer Pak, players could connect Pokémon Red, Blue, and Yellow cartridges to transfer Pokémon, organize them, and use them in 3D battles.

The title can be confusing because the Japanese release was marketed as Pokémon Stadium 2, while the international version was simply called Pokémon Stadium. A later Nintendo 64 sequel was released internationally as Pokémon Stadium 2 and supported the Gold, Silver, and Crystal games.