Geologically, the islands are characterized mainly by limestone and granite. 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. Offshore are extensive coral reefs.
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.
The area is also important for migrating cetaceans and the "Whale Bay" in the east of Kanmaw Kyun was named historical presences of large number of whales. Such variety includes resident population of Bryde's whales, Omura's whales, occasional blue whales, longman's beaked whales, strap-toothed whales, and killer whales, dolphins, finless porpoises, and Irrawaddy dolphins.
On the islands themselves, various animals thrive, including deer, monkeys, tropical birds including hornbills, and wild swine. There are even unconfirmed reports of Sumatran rhinoceros on Lanbi, one of the bigger islands, but this has been widely discredited.
Environmental threats to the region include overfishing and also blast fishing. Myanmar's current military government, the "State Peace and Development Council", has not done much to deal with these problems.
The largest and highest island is Kadan Kyun at 767 metres across the inland channel from Myeik. Other important islands are:
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. They are a sea-dwelling people and they follow a traditional way of life, doing things such as fishing and building boats very much the way they have done for centuries. They can be found living on their traditional boats during the dry season, but usually keep to land in the rainy season. The Moken claim that the islands were detached from the mainland after a great mythological flood.
The Mergui Archipelago is located in Tanintharyi Region, one of the regions heavily impacted by violence during the Burmese Civil War. Violence in the Mergui archipelago has often targeted civilians including the massacres of fishermen and the entire population of the picturesque Christie Island.
The area was only opened up to foreign tourism in 1997 after negotiations between Myanmar and dive operators from Phuket in Thailand. The archipelago's isolation is such that much of it has not even yet been thoroughly explored. The best diving conditions exist from December to April, with whale sharks and manta rays visiting from February to May. A five-star casino and golf resort, the Andaman Club now operates on Thahtay Kyun.