The water emergency was called about 4 p.m. off 100th Street in Long Beach, according to initial reports.
An unconfirmed report said the elderly swimmer had been pulled from the water and that EMTs were trying to revive her.
New Jersey authorities have been warning about rough seas all week.
On Monday, a swimmer in his 60s drowned in Lavallette and five other swimmers were rescued in Seaside Park, authorities said.
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