SOS Encounter: Route 3 (Only in Sun & Moon), Seaward Cave (Only in Ultra Sun & Ultra Moon)
Walk: Seaward Cave (20%, Only in Ultra Sun & Ultra Moon), Route 3 (10%, Only in Sun & Moon)
Surf: Seaward Cave (10%, Only in Ultra Sun & Ultra Moon)
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 Poké Ball, Premier Ball or Sport Ball.
Delibird in every game · Pokémon Sun, Moon, Ultra Sun & Ultra Moon interactive map (Alola)