I personally think the psychic-type one is the best, but that's just me.
Rrod54-I personally think flareon is the best but i am strictly high attack trainer but if u want a contest trainer i believe espeon or the psychic type is the best
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LunarPikachu's Edit:
The best evolution of Eevee really depends on what form you need, or what purpose you have for it. If you need a Pokémon with many resistances, you might go with Flareon (five types aren't very effective against it), Vaporeon (four types aren't very effective against it), or Leafeon (four types aren't very effective against it). If you were looking for a Pokémon to have different move types, you might go with Glaceon, Vaporeon, or Leafeon (who all have about 12 different attack types you can choose from).
If you're looking for the best in stats, that also depends. Vaporeon is the best if you want it to have a lot of HP. Flareon is the best if you want it to have a lot of attackpower. Leafeon is best of you want it to have a strong defense. Espeon and Glaceon are tied with the best special attack. Umbreon has the best special defense. Lastly, Jolteon has the best speed.
i personal think jolteon is the best. decent movepool and decent range of stab attacks. Also, jolteon has a high speed and a pretty good sp attack
Glacion evolves from Eevee on route 217, it doesn't evolve anymore after that.
Flareon, Vaporeon, Jolteon, Espeon, Umbreon, Glaceon, and Leafeon are the evolved forms eevee
give it a water stone
The strongest one Espeon or status problem ones Flareon Glaceon and Jolteon.
As for any and every Pokemon that's evolved they cannot return back. So if you evolved eevee into Jolteon and wanted umbreon, simply breed Jolteon with ditto, a newborn eevee will hatch. To make it happy, max it out on power ups, HP UP, Protein, etc. They can take only 10 of each, but this makes any Pokemon happy.
Espeon is the psychic evolved form of Eevee. It is a psychic pokemon.
Glacion evolves from Eevee on route 217, it doesn't evolve anymore after that.
Flareon, Vaporeon, Jolteon, Espeon, Umbreon, Glaceon, and Leafeon are the evolved forms eevee
Eevee and Growlithe Eevee, Growlithe, Ninetales pre-evolved form and slugma (I'm not sure bout Slugma).
Feraligator, Snorlax, Mewtwo, Eevee or an evolved form(preferably Jolteon), Lugia, and Teddiursa. All should be at least 70.
You have been lied to, obviously. of course it cant! whoever told you that is dupluted
Eevee.
Espeon is one of the many evolved forms of EEVEE. It is a psychic type Pokemon that can be evolved from EEVEE with happiness during the day.(before 7pm just to be safe)
Flareon, Vaporeon, Jolteon, Espeon, Umbreon, Glaceon, and Leafeon are the evolved forms eevee
Yes, as long as you haven't bred the espeon (i.e the eevee before you evolved it) from the same ditto and another eevee or eevee-lution.
Umbreon is Dark type. It is the evolved form of Eevee. It is a very powerful Dark type Pokemon.
give it a water stone