Catch per unit effort (CPUE), species composition and size of billfish from purse seine fisheries in the Andaman Sea of Thailand were studied by collecting the data from purse seiners landing along the Andaman Sea Coast from January to December in 2020 - 2022. The results showed that the CPUE of purse seiners operated in the Andaman Sea of Thailand in 2020 - 2022 was 2,406 kilogram/day divided into Indo-Pacific sailfish (Istiophorus platypterus and Black marlin (Istiompax indaca) equal 0.794 and 0.142 kilogram/day respectively. Species composition of billfish was 0.04% of the total catch divided into Indo-Pacific sailfish 0.03% and Black marlin 0.01%. The length (lower jaw to fork length; LJFL) of Indo-Pacific ranged from 40.0 - 190.0 cm and the average length was 129.0 ± 28.1 cm.