The RNLI has warned of the dangers of going into cold water after a teenager was dragged unconscious from the sea in Rhyl by a friend.
The town's inshore lifeboat was launched on Saturday night and coastguards also rushed to the scene in north Wales following 999 calls.
The boy, who had entered the water to retrieve a football, was given oxygen, warmed up, and began coming around before an ambulance arrived.
He and his friend were taken to nearby Glan Clwyd Hospital.
Paul Frost, duty lifeboat coxswain, said: "We advise all people near the sea, and even by inland waters, to Respect the Water. Even though the air temperature is warm, the water is still cold at this time of year, and can incapacitate even the strongest swimmer. It is not advisable for anyone to enter the water to retrieve a ball, especially at night.”