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

Only in Ultra Sun
Static Encounter: Ultra Space Wilds, Ultra Space

Guide: Ultra Space Wilds: Every Legendary in Ultra Sun & Moon

Tornadus also appears in

How to get Tornadus in Sun, Moon, Ultra Sun & Ultra Moon

Its base catch rate is 3 out of 255 (higher is easier); the catch rate calculator works out your odds with each ball.

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