Wadi Shab is one of the most dramatic gorges in Oman, a narrow canyon cut through the limestone mountains along the coast road between Muscat and Sur. What sets it apart from the country's many other wadis is water: the floor runs with a stream fed by natural springs even in the dry season, which is unusual enough on the Arabian Peninsula to feel genuinely remarkable. The walls rise steeply on either side, date palms and terraced smallholdings crowd the canyon floor, and at the inner end a chain of deep turquoise pools opens up where swimming is the whole point of the visit.
Reaching the wadi is part of the experience. The drive from Muscat takes about two hours along the coastal highway. From the parking area a local villager ferries you across the lagoon in a small skiff, and from there a well-worn path leads roughly 45 minutes to an hour inland, through the palms and past the falaj channels, before the swimming pools begin. The path involves some easy scrambling over rock, and the final stretch means wading and swimming, so bring shoes that can get wet and a dry bag for anything you don't want soaked.
The famous payoff lies at the furthest pool: a low, half-submerged cave entrance that you swim through into a hidden chamber inside the rock, where a waterfall drops into an underground pool. The squeeze is genuinely tight and not for the claustrophobic, but the chamber on the other side is one of those places that justifies the effort entirely.
Wadi Shab is popular enough that weekends bring real crowds, which can take some of the magic out of it. Going on a weekday, or arriving before 8am, makes a large difference. The Bimmah Sinkhole sits about 40 minutes further along the coast road toward Sur, and the two combine naturally into a full day out from Muscat.