This is the heroic moment Coast Guard staff rescued a drowning child from the sea in California.

Coast Guard Sector Humboldt Bay watchstanders received a call from the Sheriff's Office about an 11-year-old girl struggling in the water near Big Lagoon County Park on Thursday, July 17.

The watchstanders quickly sent out an urgent marine alert and dispatched a helicopter crew from Air Station Humboldt Bay, along with a Motor Lifeboat crew from Station Humboldt Bay, to respond.

California State Parks Lifeguards arrived first and helped pull the girl out of immediate danger in the surf zone, moving her to calmer waters while waiting for the rescue teams.

Footage shows the helicopter approaching the scene as a rescue swimmer jumps by freefall into the water.

The lifeguards handed the child to the rescue swimmer, who then helped her into the aircraft. Once aboard, the crew began treating her for symptoms of hypothermia.

She was then handed over to waiting emergency medical services for further treatment and transport to hospital.

Hypothermia is a medical emergency that occurs when the body's temperature drops below 95 degrees Fahrenheit (35 degrees Celsius). It can be fatal if left untreated.