Drive 1.5 hours south-east of Muscat to Wadi Shab — a steep-walled canyon with a series of emerald-green freshwater pools fed by mountain springs. A 45-minute hike along the canyon floor leads to a chest-deep wade and swim through three pools to a hidden cave waterfall. Bring water shoes and a dry bag. Combine with the Bimmah Sinkhole on the way back.

