Police Major General Taweeporn Churin said six male and three female bodies were found near two islands in Ranong province.
He says marine police previously retrieved three female bodies on Saturday after their boat sank early Saturday morning because of rough seas and bad weather.
Taweeporn says 38 people were rescued.
Ranong is 460 kilometers (290 miles) south of Bangkok and borders Myanmar.
Police says it is common for migrant workers to travel by boat to illegally enter Thailand through the province.
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