Oman is a choose-your-own-adventure dive country: protected coral islands off a capital, fjord pinnacles at the Strait of Hormuz, and a monsoon-shaped southern coast. Most scuba trips focus on Muscat and Daymaniyat Islands for reef fish, turtles, and seasonal whale sharks; Musandam, Khasab and the Fjords for walls and current-swept pinnacles; and Dhofar, Salalah and Mirbat for quieter Arabian Sea reefs and winter diving. Add Hallaniyat Islands when you want remote water, offshore scale, and marine mammal potential.
Expect warm water most of the year: around 23°C to 33°C in the north and roughly 24°C to 32°C near Salalah, with visibility that can swing from week to week.