Pokemon Scarlet & Violet Eevee Location
Eevee can be found in multiple places in the game. However the earliest you can get Eevee is once you get to Cortondo (where the bug gym is) to the west of Mesagoza. Here you will be able to find Eevees just outside to the west of the town (right next to the big field where the gym trial takes place). You may have to walk around a little before you see an Eevee since they are a but rare to see here.
Video Guide