The 999 alarm was raised by a member who spotted the person in the cold waters.
The individual was later taken to Altnagelvin hospital for treatment.
FSR say: “At 07:23 am on Saturday, 10/8/19, Foyle Search & Rescues Pager Team were tasked by the PSNI to reports that a person had entered the water.
“Mobile Units, Boat Crew and a Jet Ski were activated.
“Jet Ski arriving on scene located and secured the person who was then transferred to Boat and removed to FSR Base at Prehen.
“The Person was then assessed by an Emergency Medical Technician and Emergency First Responders.
“The Person was treated for Cold Water shock before being handed into the care of Northern Ireland Ambulance Service Paramedics prior to transfer to hospital.
“Appreciation to the member of the public who rang 999 & the PSNI for their assistance during the Rescue.”
Well done to everyone involved.