Scuba diving is extremely popular in Ko Tao due to clear visibility, inexpensive pricing, warm water, and the range of sealife to be seen.

It would appear from old maps and descriptions that this island was known by European cartographers and mariners as "Pulo Bardia", indicating that it was first settled by Malayo-Polynesian peoples.

Seventeenth century marine navigation and cartography used the "backstaff" which, in this area, was accurate to one degree of longitude, or around 60 nautical miles.

On 18 June 1899, King Chulalongkorn visited Ko Tao and left as evidence his monogram on a huge boulder at Jor Por Ror Bay next to Sairee Beach.

In 1947 Khuang Abhaiwongse, prime minister at that time, pleaded and received a royal pardon for all prisoners on the island.

The development of tourism has negatively impacted the health of these grounds, but a breeding programme organised in 2004 by the Royal Thai Navy and KT-DOC, a coalition of local scuba diving centres, has reintroduced hundreds of juvenile turtles to the island's ecosystem.

El Niño weather patterns caused a warming of the waters which resulted in the loss of a great deal of the shallow corals near the island.

[9] Natural factors combined with over-use of some areas has led to an increase in the abundance of corallivores such as Drupella snails[10] and the crown-of-thorns starfish[11] around the island in recent years.

In 2012, a Marine Zoning and Regulations Master Plan was developed for the island and subsequently become local law, but the positive effects of increased management have yet to be realized.

The most popular place for tourists is Sairee on the west coast, which has a white sandy beach of 1.7 km interrupted only by a few huge boulders and a scattering of medium budget resorts and restaurants.

Chalok Baan Khao, to the south of the island, is becoming increasingly popular as an alternative for those wishing to escape the crowds.

A great many granite boulders, both in the forests and on the beaches of Ko Tao, attract a growing number of climbers.