A 27-year-old man's body has been recovered from Ponden Reservoir after emergency services were called to the area over reports of a man getting into difficulty whilst swimming.
The man was seen struggling in the water at Scar Top near to Keighley at 5.50pm on June 15, according to West Yorkshire Police.
The man's body was found at 10pm and he has been identified as someone from outside the West Yorkshire area.
Detective Chief Inspector Andy Farrell, of Bradford District Police, said: "We are continuing to investigate today following a major search at the reservoir last night which sadly resulted in divers recovering the body of a man.
"This has been a tragic incident in which a man has lost his life and I would like to remind all residents in and visitors to West Yorkshire of the extreme dangers posed by swimming in or entering open water not designated for such use.
"Such water can be very cold, even in the summer months, and people suddenly entering cold water are susceptible to hyperventilation, which could result in the body going into seizure.
"Our thoughts are with the victim’s family and officers are working to support them as our enquiries continue."
It is the third drowning in open water in the Calendar region in the last few months - Andrea Mackowan, from the Royal Society of Saving Lives, warned that the pump mechanism in reservoirs can often lead to drowning.
Anyone who gets into difficulty in water is told to:
Temper their breathing
Lie on their back in the water in a star shape
Call for help