SOS Encounter: Route 12, Route 4, Route 6 + 2 more
Walk: Paniola Ranch (50%), Route 12 (30%), Route 4 (20%) + 2 more
Its base catch rate is 190 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 Nest Ball or Safari Ball.
Evolution: Mudbray → Mudsdale (Level 30).
Mudbray in every game · Pokémon Sun, Moon, Ultra Sun & Ultra Moon interactive map (Alola)