The Red Sea lies between arid land, desert and semi-desert. The main reasons for the better development of reef systems along the Red Sea is because of its greater depths and an efficient water circulation pattern, The Red Sea water mass exchanges its water with the Arabian Sea Indian Ocean via the Gulf of Aden These physical factors reduce the effect of high salinity caused by evaporation and cold water in the north and relatively hot water in the south.

The Red Sea is a rich and diverse ecosystem. More than 1100 species of fish^[10] have been recorded in the Red Sea, and around 10% of these are found nowhere else.^[11] This also includes around 75 species of deepwater fish.

The rich diversity is in part due to the 2,000 km (1,240 mi) of coral reefextending along its coastline; these fringing reefs are 5000-7000 years old and are largely formed of stony acropora and porites corals. The reefs form platforms and sometimes lagoons along the coast and occasional other features such as cylinders (such as the Blue Hole (Red Sea) at Dahab). These coastal reefs are also visited by pelagic species of red sea fish, including some of the 44 species of shark.

The sea is known for its spectacular recreational diving sites, such as Ras Mohammed, SS Thistlegorm (shipwreck), Elphinstone, The Brothers, Dolphin Reef and Rocky Island in Egypt and less known sites in Sudan such as Sanganeb, Abington, Angarosh and Shaab Rumi (see photo above).

The Red Sea became known a sought-after diving destination after the expeditions of Hans Hass in the 1950s, and later by Jacques-Yves Cousteau. Popular tourist resorts include El Gouna, Hurghada, Safaga, Marsa Alam, on the western shore of the Red Sea, and Sharm-El-Sheikh, Dahab, and Taba on the Egyptian side of Sinaï, as well as Eilat, in Israel in an area known as the Red Sea Riviera.