What was the first Pokémon game to feature Pokémon rendered in 3D?

Pocket Monsters Stadium was the first Pokémon game to feature Pokémon rendered in 3D.

Released in Japan for the Nintendo 64 on August 1, 1998, Pocket Monsters Stadium brought Pokémon battles into polygonal three-dimensional arenas. It connected with the Game Boy Pokémon games through the Nintendo 64 Transfer Pak.

Technical limitations meant that only 40 Pokémon could be used in battles, even though the connected Game Boy games contained 151 species. The game nevertheless represented a major visual step beyond the original handheld graphics and included tournament and free-battle modes.

It is easy to confuse this title with the internationally released Pokémon Stadium. Outside Japan, Pokémon Stadium followed in 2000 and expanded the playable roster to all 151 original Pokémon. The Japanese title is therefore the precise answer when asking about the franchise’s first 3D Pokémon game.