At MCT, stay airside—compact terminal with cafés makes staying put ideal.
Go directly to Mutrah Souq, 30 to 40 minutes from the airport by taxi (OMR 8 to 10). The covered market sells silver, frankincense, textiles, and spices in a compact, walkable space. Adjacent to the souq is Mutrah Corniche, a 3 km seafront promenade with views of the harbor and old forts. Allow 60 to 90 minutes in the area and depart for the airport 45 minutes before your self-imposed departure buffer.
Mutrah Souq (90 minutes) plus the Bait Al Zubair Museum (OMR 2 / $5.20 entry, Tuesday to Sunday 9:30 AM to 6 PM) covers Omani history and heritage in the Mutrah-Old Muscat area. The Old Muscat district (Al-Alam Palace, Al-Mirani Fort exterior) is a 10-minute taxi ride from Mutrah Souq (OMR 3 to 4). Budget OMR 25 to 35 including taxis and entry fees for a 6 to 8 hour circuit.
Sultan Qaboos Grand Mosque is open to non-Muslims Saturday to Thursday, 8 to 11 AM. It is 15 km west of Mutrah (OMR 5 by taxi), with 20,000-worshipper capacity and one of the world's largest hand-woven carpets. Pair with Mutrah Souq and the Corniche for a full morning. The Royal Opera House exterior and surrounding Shati Al Qurm area fills an afternoon.