Fresno County Fire/CAL FIRE responded to a call of people stuck in a tree on an island around 12 p.m. Thursday between Goodfellow and E Annadale avenues.
Officials believe they got into the river at Annadale Avenue with their raft but, at some point, lost it.
Investigators do not know how long they were in the water.
When CAL FIRE arrived, they were able to get a drone into the air to locate everyone in the river.
Firefighters then launched a boat with a rescue swimmer to get everyone on board.
No one was injured.
Firefighters say this was the best-case scenario with everyone not being hurt.
Stay with ABC30 for the latest details on this developing story.