In this research, some physicochemical properties and lead (Pb), mercury (Hg) and cadmium (Cd) concentrations of the thirty-two sea water samples from Tanintharyi coastal zone in Myanmar were determined and compared with acceptable levels of international and ASEAN standards. The average dissolved oxygen (DO) and total suspended so lid (TSS) values were found to be 5.46 ppm and 7.06 ppm, respectively. These values were lower than the acceptable levels for aquatic life protection. The concentrations of ammonia nitrogen (0.031 ppm), nitrite nitrogen (0.026 ppm) and orthophosphate (0.025 ppm) were under the acceptable levels of ASEAN and other countries. It can be deduced that the studied regions are not eutrophicated with nitrogen and phosphorus species. Average concentrations of Pb, Hg and Cd were found to be 5.64, 0.65 and 1.95 ppb, respectively. These values (except Hg) were lower than the acceptable levels of ASEAN