Thomas Reef.

• Plateau at about 25 m, with sharks resting on sand patches
• Gorgonian fans, whip corals and soft corals
• Overhangs and small caves at the northern end
• Thomas Canyon from about 35 m (technical depths)
• Arches within the canyon

• Sharks resting on the plateau's sand patches
• Leopard sharks
• Sharks passing between Thomas and the neighbouring reefs
• Gorgonians, whip corals and soft corals

The reef top comes to within about a metre of the surface, and a plateau lies at about 25 m on the south-east side. Recreational dives stay within 30 m. Beyond the plateau, a narrow canyon running parallel to the reef starts at about 35 m. Wannadive's canyon entry gives arches at about 39 m and 54 m and a floor of 59 m under the second arch; its reef entry says the canyon runs from about 30 m to 90 m or more. The canyon is beyond recreational limits.

Currents can be strong at the northern and southern ends. There is no mooring, so the reef is dived as a drift, usually entering at the south-east point and moving north. The western side is often too rough for boats to pick divers up, so the dive depends on the weather (Red Sea Diving College). It is rated advanced. Boat time from Sharm el-Sheikh is about 1½ hours (liveaboard.com). Protected status: Tiran Island was part of Ras Mohammed National Park (Wikipedia); the sources consulted do not state the reefs' own designation or whether a park fee was charged for them in 2007–09. pro-taucher says passports and the full Egyptian visa were needed for trips to the Tiran reefs. Tiran Island was transferred to Saudi Arabia in 2017 (see region notes).