Which accessory let players trade and battle Pokémon between Game Boy systems?

The Game Link Cable let players trade and battle Pokémon between Game Boy systems.

Nintendo designed the cable to connect compatible Game Boy consoles directly. In the original Pokémon games, two players could use it to exchange Pokémon or battle one another, turning the series’ central idea of cooperation into a physical multiplayer feature.

Trading was especially important because Pokémon Red and Green, and later Red and Blue, contained version-exclusive species. No single player could normally obtain every original Pokémon from one cartridge. A second system, another game, and a Game Link Cable were therefore part of the intended route to completing the Pokédex.

The Game Link Cable was wired and connected through the Game Boy’s link port. It is sometimes confused with the Nintendo 64 Transfer Pak, which moved compatible data between Game Boy cartridges and Nintendo 64 games, or with the later Wireless Adapter used by some Game Boy Advance titles. Pokémon’s trading concept predates both of those accessories and helped demonstrate why handheld multiplayer could be valuable even without online connectivity.