Danang police on June 17 arrested the boat owner Vo Quoc Hung, 44, and Nguyen Ngoc Quan, 25, a tour guide who was responsible for selling the boat tour to customers. The pilot, Le Cong Chi, was arrested earlier.
Two children and a man drowned after the Thao Van 2 tourist boat overturned on the Han River on June 4 evening.
According to the police, the boat was not licensed to carry tourists.
The police considered overloading the primary cause of the sinking. The vessel, which was originally a fishing boat, had a capacity of only 28 passengers, but was carrying 56 people when it capsized.
The reputation of Danang's tourism industry has suffered from the sinking, said the chief of Danang Party Unit, Nguyen Xuan Anh.
Following the tragedy, Danang authorities suspended the operation of all tourism boats on the Han River.
They also suspended the issuing of license for tourist boats modified from fishing boats.
Investigation is ongoing.
