Eevee is a special Pokémon as the evolution is a random of one of three Pokémon, namely, Vaporeon, Flareon or Jolteon.
There is a trick to choose your evolution by renaming your Eevee to one of the trainer names from The Battling Eevee Brothers Pokémon episode before evolving.
| Trainer Name | Evolution |
|---|---|
| Rainer | Vaporeon |
| Pyro | Flareon |
| Sparky | Jolteon |
Remember that Vaporeon has the highest CP followed by Flareon, and Jolteon has the lowest CP among the three. Vaporeon is also one of the highest HP Pokémon in the game.