Diversity and distribution of seaweeds at Khanom-Mu Ko Thale Tai National Park, Nakhon Si Thammarat Province, Thailand were carried out between October 2005 and May 2008 at five islets, Ko Taen, Ko Mut Sum, Ko Rab, Ko Wang Nai, and Ko Wang Nok. A total of 60 species were identified including 23 species of Chlorophyta, 19 species of Phaeophyceae in the Chromophyta, 16 species of Rhodophyta, and 2 species of Cyanobacteria. Of these, eight species are believed to be new records for the Thai marine flora. The number of species varied from site to site. Ko Tan had the highest diversity with 49 species and KoWang Nok had the lowest diversity with 22 species. This study provides a more complete species list for further comparative studies between the Gulf of Thailand and the Andaman Sea. We have intensively reviewed the seaweed literature of Thailand, which was very limited. However, recent work on population and community structure have increased from 2005, which helps providing a baseline for future, more complex ecological studies, as well as for coastal management and for the exploration of the seaweed’s economic potential.
