This site is on a generally steep sloping reef, which includes some plateau sections and a very deep canyon running along the reef's southern section. It is the smallest of the four Tiran reefs, and its position in the chain leaves it exposed to some fairly vigorous currents.

The reef's upper section is a riot of color, encompassing some of the finest soft coral growth in the Sinai region. Huge, densely packed fields of Dendronephthya of every imaginable hue are spread across the reef, along with antler corals, fine Stylophora, some Acropora and many other stony coral forms.

Fish life is also rich, with the greatest concentration in the shallows. Lyretail cod and other groupers grow to great size, and many varieties of rabbitfish and wrasse congregate along the reef face, accompanied by box and pufferfish.

The only reason to go much deeper than 20m (65ft) at Thomas Reef is to explore the canyon; an option for only very experienced deep divers. You should not even consider this hazardous option without consulting your dive guide.