The accident was the second major disaster on Uganda's lakes in three days.
"There was a party on the boat, the passengers were dancing and others were drunk. The boat was overloaded with 45 people, all members of the football team and local fans," police commander John Rutagira told AFP.
"The water was calm but the problem came in when the merrymaking team and fans tilted on one side of the boat... It capsized killing about 30 people," he added.
Police officers working with local fishermen managed to rescue 15 of the revellers, who were heading from the village of Kaweibanda in the western Buliisa District to watch a friendly Christmas Day match in Hoima District, Rutagira said.
The accident was the second major disaster on Uganda's lakes in three days. On Friday, about 20 people perished in similar circumstances on Lake Victoria.
Fatal accidents are frequent on Ugandan waters. Last November, 10 people drowned in Lake Albert on the country's western shore.