Question: how to evolve eevee into jolteon in pokemon ultra moon?
Answer: You will need to use a Thunder Stone on an Eevee in order to evolve it into a Jolteon. You can obtain the stone by getting it from an old man on Route 9 on Akala Island, dig it up with your Pokémon at Isle Aphun on Poké Pelago, or purchase it from the shop at Konikoni City on Akala Island for ₽3,000.