Level 20.
Magikarp can evolve into Gyarados, starting at level 20.
magikarp evolves into gyarados at level twenty in any Pokemon game.
In Pokémon Ruby, Magikarp will evolve into Gyarados at Level 20.
Gyarados doesn't evolve as it is the max evolve form of magikarp. Magikarp evolves into Gyarados at level 20.
Magikarp evolves into Gyarados at Level 20.
Magikarp evolves into a Gyarados at level 20.
Magikarp evolves into Gyarados at level 20.
Magikarp evolves into Gyarados at level 20
Magikarp evolves into Gyarados at level 20.
Magikarp evolves at LEVEL 20 to Gyarados.
Magikarp evolves into Gyarados at level 20
Magikarp evolves into Gyarados starting at level 20.