The passengers were caught in the fire around 3 a.m. while sleeping in private bunks downstairs, officials said.
The 20-foot boat was moored just off Santa Cruz Island, 140 miles from Los Angeles when the fire broke out.
Unknown how it started, 5 people who noticed the fire survived by jumping into the sea.
About 40 people on the boat slept during the fire, of which at least 25 died.
Search for 10 missing people continues.
ILKHA