Jeddah sits on one of the richest stretches of the Red Sea — vibrant fringing reefs, drop-offs, and a string of historic wrecks. The water is warm year-round (22°C in winter, 30°C in summer), visibility is regularly over 30 metres, and the reefs are far less dived than the equivalent sites on the Egyptian side.
The best operators run day boats from Obhur Creek, half an hour north of the city, with two or three dives a day. Standout sites include the Boiler Wreck off Abu Madafi, the Ann Ann (a 1970s cargo ship at recreational depths), and the wall dives off Mukrey reef. PADI courses available; expect to pay more than in Egypt.