How do you get Raikou in Pokemon Fire Red?
To encounter a Raikou in Pokemon FireRed, you need to have chosen a Squirtle as your starter Pokemon. You also need to have defeated the Pokemon League. Then, it is only a matter of chance as Raikou runs wild through Kanto. Remember that if you fly somewhere, the Pokemon will run to the opposite side of Kanto from you. Simply walk through patches of grass and you may encounter it.
