Two children who were trapped inside an overturned boat were among seven people rescued from Tomales Bay just south of Bodega Bay Sunday afternoon, according to rescuers.

The 25-foot pleasure craft, which is owned by an Elk Grove, Calif. resident, capsized near the mouth of Tomales Bay shortly before 1:30 p.m., triggering calls to several agencies, according to Marin County Fire Department Battalion Chief Mike Giannini.

A Sonoma County Sheriff's Office rescue helicopter arrived first on the scene, to find five people, three adults and two children, clinging to the hull of the overturned boat, Giannini said.

Waves were battering the boat, and one of the adults was holding a 3-year-old child in her arms, according to Sgt. Ed Hoener with the Sonoma County Sheriff's Office.

The helicopter rescued the 3-year-old first, and then brought the others to shore, one by one.

However, rescuers soon realized that two other children remained trapped inside the cabin of the overturned boat, which was filling with water.

A U.S. Coast Guard rescue swimmer and a Marin County fire captain were able to make contact with the children and determine they were still alive and uninjured by tapping on the hull and calling to them, Giannini said.

A National Park Service rescue boat then towed the capsized boat to the shore near Dillon's Beach. Firefighters were able to cut a hole in the hull there to talk to the children, and then cut a larger hole to get them out, Giannini said.

The children who had been trapped were taken by helicopter to Petaluma Valley Hospital. Two adults and two other children were also taken there by ground ambulance. One male adult suffered a minor injury and all the boaters were evaluated for hypothermia.

No one on the capsized boat appeared to have been wearing a life jacket, Giannini said. It is unclear what caused the boat to capsize.

"These folks are very lucky to be alive today," Giannini said.

In addition to Marin County fire, the Sonoma County Sheriff's Office and the Coast Guard, the Bodega Bay, Petaluma and Tomales fire departments also responded to the rescue.