Oman is a brilliant place to spend ten days without spending ten weeks planning. But if you're using its 14-day visa-exemption arrangement, your flight home deserves attention before you leave. Oman's Foreign Ministry explicitly lists a return ticket among the conditions for that arrangement. If you have booked only your flight into Muscat, sort out the return-flight plan before airport check-in—not while the queue forms behind you.
The useful question is not simply Do I need a ticket? It is Which return itinerary actually fits the trip I intend to take?
Start with your final night, not your arrival flight
Imagine a London-based traveler planning eight nights in Oman. They land in Muscat on November 6, spend two nights in the capital, drive toward Nizwa and Jebel Akhdar, then finish with a couple of quiet days on the coast. Their return is planned for November 14.