Only in Ultra Sun & Ultra Moon
SOS Encounter: Hau'oli City (15%)
Gift: Poké Pelago
Its base catch rate is 45 out of 255 (higher is easier); the catch rate calculator works out your odds with each ball. For the look, the best colour match is Heal Ball, Dream Ball or Premier Ball.
Evolution: Mime Jr → Mr Mime.
Mr. Mime in every game · Pokémon Sun, Moon, Ultra Sun & Ultra Moon interactive map (Alola)