First of all, you can perform stone-based evolutions on Pokémon of any Level; 1, 100, or anywhere in-between, it's irrelevant as long as the Pokémon can evolve with a Stone.
Second, Eevee evolves into Umbreon through happiness rather than using a Moon Stone. To raise its happiness, feed it vitamins, take it to be groomed, keep it in your party, keep it from fainting, help it level up. When its happiness is high enough, it will evolve the next time it levels up. But be sure that it's nighttime; if Eevee evolves through happiness in the daytime, it will become Espeon.
One further footnote: as there is no clock mechanic in FireRed and LeafGreen, it is impossible to evolve Eevee into Espeon or Umbreon in those games.
You have to make Eevee really happy while it's is evolving,there is no certain level that will make Eevee evolve.
To evolve Eevee into Umbreon in Pokémon SoulSilver, you need to ensure that your Eevee has high friendship (at least 220). Once this friendship level is reached, you must level up Eevee during the night (between 8 PM and 4 AM in the game). Make sure to avoid leveling up during the day, as this will not trigger the evolution into Umbreon.
To evolve Eevee into Umbreon, you need to train it during the night while ensuring it has high friendship with you. You can level up your Eevee in areas like caves or forests where wild Pokémon are present, or you can participate in battles with trainers. Once its friendship is sufficiently high, level it up at night, and it will evolve into Umbreon.
By getting EEVEE to a high friendship level at night.
You get it by making it max friendship can do it faster if you give it a massage at one veilstone city's houses. If you have a poke app that tell you the friendship you can see it .Give it a poffin and a massage then it will get to a umbreon no time. P.S.: Do it at night or it will be espeon.
You need to make Eevee love you, and then you evolve it at night.
Make Eevee as happy as you can. For Umbreon, level it up at night. For Espeon, level Eevee up in the day.
To make Eevee evolve into an Umbreon, you have to level it up with high happiness at night.
Sorry to say but, eevee doesnt evovle into umbreon by level. The only way to make it evolve at night with high happiness
Eevee doesn't have a set level to evolve into Umbreon. All you have to do to evolve it is max out its happiness at night. ~KKMG1
You will need to have your Eevee to full Happiness, then level it up at least once during the night to evolve it into Umbreon.
To get an Umbreon, you must gain high friendship with an Eevee and level up at night.
Level up your Eevee with high friendship at night
get eevee at full hapiness then level it up
you have to level him up at night
I believe that you have to get the eevee to max happiness ( or really high ) and level it up in the nighttime.
Umbreon. It's the Dark type. Level up an Eevee at night when it likes you.