A boat carrying 20 people capsized and sank near Alcatraz Island, killing one person while injuring three and leaving three others unaccounted for, city officials said.

The small passenger craft went down close to the island that sits in the center of San Francisco Bay. According to city officials, the vessel capsized and sank, leaving a chaotic scene as responders converged on the water.

At least one person was confirmed dead, and three others were reported injured in the aftermath. Three additional people remained missing as crews continued search efforts, and officials described the situation as an active rescue operation.

Emergency units arrived quickly, with boats and responders working together to pull people from the cold water. Witnesses on nearby vessels and shorelines described a fast-moving response as crews searched the area where the boat went under.

Officials have not released details about what caused the capsizing, and investigators have not completed a full accounting of the sequence of events. For now, authorities are focused on locating the missing and treating the injured while preserving evidence for a formal probe.

San Francisco Bay is known for strong currents and sudden weather shifts that can challenge even experienced mariners. Those conditions can turn a manageable problem into a life-threatening emergency in minutes, which is why local responders train for swift water and maritime rescues.

Family members and onlookers gathered along parts of the waterfront as the incident unfolded, and emotions ran high as updates came in from city officials. Emergency personnel worked to keep people back from the shoreline to allow search and rescue teams room to operate safely.

The city emphasized that the counts and medical conditions were preliminary and subject to change as responders complete their work. Officials urged patience while they coordinate across agencies to get a clear picture of exactly what happened and who remains affected.

Once the immediate rescue phase concludes, authorities will turn to a detailed investigation to determine causes and any possible safety lapses. That follow-up will be key to understanding whether weather, vessel condition, operator error, or other factors contributed to the tragedy near Alcatraz Island.