Where to find Drowzee in Sun, Moon, Ultra Sun & Ultra Moon

SOS Encounter: Route 2
Walk: Route 2 (30%)
Surf: Route 2 (35%, Only in Ultra Sun & Ultra Moon)

Drowzee also appears in

How to get Drowzee in Sun, Moon, 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 Ultra Ball.

Evolution: Drowzee → Hypno (Level 26).

Drowzee in every game · Pokémon Sun, Moon, Ultra Sun & Ultra Moon interactive map (Alola)