Rename Eevee to Tamao to get Umbreon in Pokémon GO. That name trick works once per evolution line , so if you’ve already used it, you’ll need the buddy-and-night method instead.

Quick Scoop

  • Umbreon nickname: Tamao.
  • Alternative method: make Eevee your buddy, walk 10 km , then evolve it at night.
  • Tip: the nickname trick is a one-time shortcut, so save it for the Eeveelution you want most.

If you want the safest method

  1. Set Eevee as your buddy.
  2. Walk 10 km with it.
  3. Keep it as your buddy.
  4. Evolve it after dark.

Tiny note

If you meant the main-series games instead of Pokémon GO, the naming trick doesn’t apply the same way.