The deceased was identified as Jiten Mondol, 60, of Kathalbaria village in the upazila.
The missing were Dilip, 32, of Faradpur village, and Horen Saha, 65, of Dumuria village.
A diving team of the Fire Service is conducting a search operation to rescue them.
Maksudur Rahman, in-charge of Premtali Police Investigation Center, the boat sank carrying 20-25 people sank in the river due to strong current.
They were going to join the funeral of a relative of Premtoli village.
Though most passengers managed to swim ashore three people went missing.
Later, locals rescued Jiten Mondol and took him to Premtali Health Complex where doctors declared him dead, reports UNB.