We found 10 bodies last night and one this morning,” said a monk from Kyauk Kar village in the southern Tanintharyi region, from where the boat had left Sunday evening.
According to the monk, who asked for anonymity to talk to the media, the boat had been carrying mostly students returning to Myeik city from the village after a two-week break.
“The boat left from the village at 9 pm (1430 GMT) which was too late already, and it was overloaded and sunk,” he said.
Villagers had carried out cremations for the 11 bodies that had been recovered, he said, and local rescue teams were searching for the missing.
None of the recovered bodies were of students, the monk said.
Boat accidents are common in Myanmar, a country with rudimentary transport and weakly enforced safety regulations.
Vessels ferrying people along the coastline and rivers are often dangerously overcrowded, and accidents can have staggering death tolls. It can also take several days for all bodies to be retrieved.