The entire group was part of a bachelor party aboard a wine-tasting cruise boat. The 40-foot-vessel hit a rocky patch near Alcatraz island on Friday night, leaving the boat with a 1-foot gash. It began taking on water and started to sink.
Passenger Matthew Rice said the group was on the boat for about 20 minutes before a big jolt shook the vessel.
"Next thing we know, the Coast Guard boats came in and got us off," described Rice.
A Coast Guard boat happened to be nearby, taking on board most of the Neptune's 22 passengers and crew and calling another Coast Guard vessel that picked up the rest.
The boats took the passengers to San Francisco's Pier 39. There were no reports of injuries.
The Associated Press contributed to this report.