The classic Jumeirah waterpark under the Burj Al Arab: 30 rides, compact and easy for a half day.
Wild Wadi is smaller than Aquaventure and better for it if you have younger children or only half a day: everything is within a few minutes' walk, the Jumeirah Sceirah is one of the steepest slides in the region, and the Master Blaster water coasters push you uphill. The Burj Al Arab is the backdrop from every pool.
It is on the beach road in Jumeirah, 15 minutes from Downtown. Hotel guests of Jumeirah properties get free entry, which keeps queues moderate for everyone else on weekdays.