A 36-year-old Ewa Beach woman — mother to a 5-year-old boy and wife of a military service member — died after their kayak capsized Monday in waters off Leeward Oahu.

The Honolulu Medical Examiner’s Office identified her as Eunhee Lee. An autopsy is expected to be performed to determine the exact cause of death.

Honolulu firefighters and Ocean Safety personnel responded to a 911 call from a military man who reported his wife missing at 12:38 p.m. Monday after a kayak they were on with their son capsized in waters approximately 500 yards from the shoreline.

The kayak overturned in an area between Oneula Beach Park, also known as “Hau Bush,” and White Plains Beach.

The man also reported his wife was not wearing a flotation device.

Ocean conditions were rough with 2- to 3-foot wave faces and wind of at least 15 mph at the time rescue crews searched the area, according to John Titchen, chief of the Ocean Safety and Lifeguard Services Division.

Titchen said the man and his son were onshore when Ocean Safety arrived at the scene.

At approximately 1 p.m., firefighters and lifeguards noticed an unresponsive person later identified as Lee on a reef. They brought her to shore at White Plains, where they administered cardiopulmonary resuscitation and used an automated external defibrillator.

Lee was taken to The Queen’s Medical Center-­West Oahu where she was pronounced dead.

Her husband and their son were not injured. Titchen noted the son was wearing a flotation device when they arrived on scene and the kayak was brought to shore.

Titchen said oceangoers should know the weather conditions and use safety gear. “In this situation, flotation devices of some sort is crucial and critical if you’re not familiar with the area or familiar with the recrea­tional activity you’re choosing,” he said.

He also said people should know their limits, research the area they plan to visit and have a strategy for getting out of the water should there be a mishap.

Kayak tour companies recommend immediately grabbing hold of a capsized kayak. “It’s the biggest flotation device,” said Coda McLaws, manager of Active Oahu Tours and Activities, who said the public should be aware that the ocean “is really unpredictable.”

Winds and a swell could cause a rip current that could cause a kayak to overturn and drift away, McLaws said, noting it doesn’t take long for a kayak to get separated from paddlers who fall out.

David Elgas, owner and operator of Coastal Kayak Tours, said they “demand” all their clients wear life vests on tours. “If you fall out, it’s a little too late to put it on.”

He echoed Titchen’s sentiment that oceangoers should know their limits. “That’s super important. It doesn’t matter if you’re local here and you can swim like a dolphin,” Elgas added.

He also emphasized that kayakers should stay together if their vessel overturns. “The No. 1 cause of death is separation from the group in an accident,” Elgas said.

He recommended that kayakers bring a VHF radio, cellphone and flares. A VHF radio is vital, Elgas said, because the Coast Guard receives a distress call in the event of an emergency and alerts nearby boaters.