The incident happened around 10 p.m., when, according to police, two Jet Ski's collided, throwing four people - two men and two women - into the water.
Authorities say one of the women was knocked unconscious in the crash. Members of the NYPD Harbor Unit pulled the victims from the water and attempted to revive her.
She was rushed to the hospital, where she was pronounced dead.
Her identity has not been released.
Police say the investigation into the circumstances of the crash is ongoing.
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