Which Pokémon game was the first to include the Pokéwalker accessory?

The first Pokémon games to include the Pokéwalker accessory were Pokémon HeartGold and SoulSilver. These Nintendo DS games launched in Japan in 2009 and came bundled with a small wireless pedometer designed to extend the game beyond the console.

Players could transfer one Pokémon from HeartGold or SoulSilver to the Pokéwalker, then carry it while walking. Steps generated watts, an in-device currency used to discover wild Pokémon and obtain items. The accessory communicated with the DS game card through infrared technology, making it a distinctive feature of these remakes.

HeartGold and SoulSilver are enhanced remakes of the 1999 Game Boy Color games Pokémon Gold and Silver. They retained the Johto setting while adding features such as Pokémon following the player in the overworld and the Pokéathlon. The Pokéwalker was not part of Pokémon Diamond and Pearl, Pokémon Platinum, or Pokémon Black and White, which is why HeartGold and SoulSilver are the canonical answer.