Only in Ultra Sun & Ultra Moon
SOS Encounter: Akala Outskirts (30%), Route 8 (30%)
Its base catch rate is 75 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 Quick Ball or Dive Ball.
Evolution: Chinchou → Lanturn (Level 27).
Lanturn in every game · Pokémon Sun, Moon, Ultra Sun & Ultra Moon interactive map (Alola)