SOS Encounter: Route 1, Route 15, Route 16 + 1 more
Walk: Route 1 (20%), Route 15 (20%), Route 16 (20%) + 1 more
Gift: Poké Pelago (Only in Ultra Sun & Ultra Moon)
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 Heal Ball, Dream Ball or Love Ball.
Evolution: Slowpoke → Slowbro (Level 37) · Slowking.
Slowpoke in every game · Pokémon Sun, Moon, Ultra Sun & Ultra Moon interactive map (Alola)