SOS Encounter: Wela Volcano Park, Route 8 (Only in Ultra Sun & Ultra Moon)
Walk: Wela Volcano Park (30%), Route 8 (15%, Only in Ultra Sun & Ultra Moon)
Gift: Poké Pelago (Only in Sun & Moon)
Its base catch rate is 255 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 Timer Ball or Repeat Ball.
Evolution: Fletchling → Fletchinder (Level 17) → Talonflame (Level 35).
Fletchling in every game · Pokémon Sun, Moon, Ultra Sun & Ultra Moon interactive map (Alola)