You must import him/her in from another game.
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.
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.
By getting EEVEE to a high friendship level at night.
If you want Eevee to evolve into Espeon then train it during the day, other way 'round for umbreon (On LGFR you need the National Dex)
Train your Eevee at night and with happiness. It will eventually evolve into Umbreon.
Eevee doesn't evolve into Umbreon with a stone. Eevee evolves into Umbreon when it is levelled up with high happiness during the night.
To make Eevee evolve into an Umbreon, you have to level it up with high happiness at night.
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.
you have to raise eevee at night
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
No, you cannot do so in LeafGreen. While Eevee can normally evolve into Espeon and Umbreon without stones, the lack of a time system in the game prevents Eevee from evolving into one of them.
in the morning, after 8:00, you evolve eevee into espeon, at night, after 8:00, it evoles into umbreon (make sure eevee likes you alot)
friendship at night
Eevee doesn't evolve into Umbreon via leveling up. Eevee doesnt evolve into any form that way actually. The eevee will need to gain a level at night, and your "friendship" will have to be high enough
You receive an umbreon from evolving eevee. You need to befriend eevee and then engage in a battle (at night on the game) and it should evolve into a umbreon.
Make Eevee as happy as you can. For Umbreon, level it up at night. For Espeon, level Eevee up in the day.