The vessel, named The Erik, left San Felipe on Saturday and abruptly sank just 60 miles south, off the Baja California Peninsula, in what is described as a "freak storm." Two rogue waves hit the boat, causing it flip.
Rescuers are extending their search because they say the missing tourists could still be alive in the warm, calm waters. Most of the 44 people on the boat were able to swim to shore.
Nineteen fishermen, most of them from Northern California, and all of the 16 crew members have been rescued. All of the rescued fishermen are said to be in good condition after more than 16 hours in the water.
In addition to the Mexican Navy's helicopters and boats, the U.S. Coast Guard has a large aircraft on the scene to help with the search.
The boat capsized on the second day of a weeklong fishing trip the group had organized for several years each Independence Day holiday.
The Erik has been on the Gulf of California, known in Mexico as the Sea of Cortez, since 1989, according to the website of the company Baja Sportfishing Inc. It was built in Holland and was equipped with stabilizers to handle the turbulent North Sea.
The California Secretary of State website says Baja Sportfishing's business license has been suspended. It doesn't state a reason or give a date.
The company said on its website Monday that all trips have been canceled.
The Associated Press contributed to this report.