Grand Mosque in the morning, a long lunch, then the Mutrah corniche and souq at golden hour.
Day 2
Old Muscat
National Museum, Bait Al Zubair and Al Alam Palace; end with an evening at the Opera House.
Day 3
Sea Day
An early dolphin trip or snorkelling, then a slow afternoon on Qurum or Al Bustan beach.
Day 4
Interior
Drive to Nizwa for the fort and souq; add Jebel Akhdar or Birkat Al Mouz if time allows.
Day 5+
Wadis & Sands
Wadi Shab and Bimmah on the coast road, or an overnight in Wahiba Sands.
Honest thought: Muscat is spread out and best enjoyed slowly. Two days cover the city’s highlights; five let you add the mountains, a wadi and the sea without rushing.