It consists of more than 800 islands, varying in size from very small to hundreds of square kilometres, all lying in the Andaman Sea off the western shore of the Malay Peninsula near its landward (northern) end where it joins the rest of Indochina.

They are generally covered with thick tropical growth, including rainforest, and their shorelines are punctuated by beaches, rocky headlands, and in some places, mangrove swamps.

The archipelago's virtual isolation from most of mankind's influence on the natural environment has given the islands and the surrounding waters of the Andaman Sea a great diversity of flora and fauna, contributing to the region's growing popularity as a diving destination, representing endangered megafaunas such as whale sharks and dugongs.

Malays and Chinese traders used the inner waters to escape the southwest monsoon, while larger ships avoided the complicated maritime geography.

The local people are an ethnic minority called the Moken, sometimes known as Sea Gypsies, although this term actually covers several groups in Southeast Asia.

Violence in the Mergui archipelago has often targeted civilians including the massacres of fishermen and the entire population of the picturesque Christie Island.