Rescuers have pulled 29 bodies, including eight children, from the sea after the military aircraft came down near the southern town of Launglon.
A total of 15 children were on board, the military said. The search is continuing but experts have warned that the chances of anyone surviving is unlikely.
One relative, Yuzana, 19, whose parents and younger brother were on board, said: “I only want to cry, I have nothing.”
The Chinese-made Y-8F-200 took off from the southern coastal town of Myeik at 1.06pm local time on Wednesday and was heading to Myanmar’s largest city, Yangon.
It was on a regular, weekly flight that takes in several coastal towns.
Those on board included 106 soldiers and family members and 14 crew, the military said.
Myanmar’s military said it lost contact while flying at 18,000ft over the Andaman Sea, 29 minutes after take-off.
The cause of the incident is yet to be confirmed.
It is monsoon season in Myanmar but there were no reports of stormy weather in the area at the time.