Emergency services worked for hours to find the boy's body from Gullet Quarry near Malvern in Worcestershire.
"This appears to have been a tragic accident and our thoughts are with the boy's family and friends at this sad time.
"While it is too early to give a cause of death, we would like to take this opportunity to remind people about the dangers of open water.
"With the warm weather upon us and the school holidays approaching, we would advise people to think twice about going into local rivers, lakes and canals in order to cool off.
"We are privileged to live and work in a beautiful part of the country with a huge area of water. However, this comes with its dangers and we would appeal for people to recognise the risks associated with water and act responsibly."
– Detective Inspector Richard Rees, West Mercia Police
A teenage boy has died after swimming in a lake at an old quarry in the Malvern Hills.
Emergency services were called to Gullet Quarry near Upper Colwall on the Herefordshire-Worcestershire border at around 1.20pm, after reports the teenager had failed to resurface after swimming in the water.
The body of the boy, who has not yet been identified, was found just before 5.00pm by firefighters and a dive team from South Wales Police.
The incident is not being treated as suspicious by police.