It is known to evolve into one of seven different Pokémon by various methods.
*Vaporeon when exposed to a Water Stone
*Jolteon when exposed to a Thunderstone
*Flareon when exposed to a Fire Stone
*Espeon when leveled up with high happiness during the daytime (Generation II onward, excludes areas with a Moss or Ice Rock)
*Umbreon when leveled up with high happiness during the nighttime (Generation II onward, excludes areas with a Moss or Ice Rock)
*Leafeon when leveled up near a Moss Rock (Generation IV onward)
*Glaceon when leveled up near an Ice Rock (Generation IV onward)
Eevee has an irregular genetic code and can sometimes evolve in accordance with its environment. Seven evolutions for this Pokémon have been discovered so far. Three of these evolutions are the result of Eevee being exposed to either a Fire Stone, Thunderstone or Water Stone. Two more of the evolutions involve maximum affection with the Trainer and are determined by the time of day. The final two evolutions are the result of training in two specific areas, Eterna Forest and Pinwheel Forest, and Route 217 and Twist Mountain.