From Table showed seawater characteristics of surface water in Ranong and Phang Nga (March 2005), the Andaman sea, Thailand. Where the sea surface temperature in Ranong and Phang Nga is between 30.05-31.90 ° C. and 30.01 to 31.25. ° C. mean value sea surface temperature 30.03 ± 0.4 ° C. Surface salinity ranged from 32.98–34.80 and 32.90–33.41 psu. Silicate-silicon varied from 3.77–25.23 µM. Ammonium-nitrogen concentration in surface water in Ranong ranged between 8.45-14.08 µM, while in Phang Nga, it ranged from 9.99–25.11 µM, Orthophosphate-phosphorus concentrations of surface water in Ranong ranged between 0.34-0.77 µM, while in Phang Nga the values ranged from 0.13–0.49 µM. Chlorophyll a concentrations in Ranong ranged between 1.34 and 4.67 µg/l. In Phang Nga waters, chlorophyll a concentrations ranged from 0.57–6.45 µg/l. with a mean value of 2.37_0.75 µg/l. and 2.0 1.6 µg/l.