To get an Umbreon in Pokémon Go, you need to name your Eevee "Tamao" before evolving it. Its important to note that this naming trick only works once per evolution type, so you can only use it to get one Umbreon. After that, youll need to evolve Eevee into Umbreon the old-fashioned way, by walking with it as your buddy Pokémon for 10 kilometers and then evolving it at night.