Which version replaced Pokémon Green outside Japan in the original releases?

Pokémon Blue replaced Pokémon Green outside Japan in the original releases.

Japan received Pocket Monsters Red and Green in 1996, followed later that year by a revised Blue version. When the games were prepared for international markets, the Japanese Blue version provided the technical and graphical basis for the games released as Pokémon Red and Blue.

This history explains why many players know the first international pair as Red and Blue even though the original Japanese pair was Red and Green. The Japanese Green version was never released internationally in its original form.

Pokémon Yellow followed as an enhanced edition influenced by the anime. It gave players Pikachu as their first Pokémon and added anime-related elements, but it did not replace Green in the international version naming. Blue is the specific answer for the international counterpart.