Evolve Onix into Steelix in Pokémon Legends: Z-A with a Metal Coat

Onix evolves into Steelix in Pokémon Legends: Z-A through a trade evolution while holding a Metal Coat. This method requires obtaining a Metal Coat, which is available later in the game's story or post-game. Once equipped, Onix must be traded to another player to trigger the evolution. Onix can be found in Lumiose City's Wild Zone 14, specifically on the northern and eastern sides or near holes.