Lithuanian-born Artur Sevcov, 32, had spent the day at the beauty spot with his family and friends on Saturday, August 26 and his body was found by the emergency services the following day.
The inquest into his death was opened by West Yorkshire Coroner David Hinchliffe at Wakefield Coroners’ Court this morning.
The short hearing was told that Mr Sevcov - a married production worker who lived on Cottingley Crescent, Leeds - had been at the site all day and had been in the water several times but stayed close to the bank.
At around 7.30pm he entered the water again and swam to the centre of the lagoon as witnessed by local anglers.
He then went under the water and never resurfaced.
The alarm was raised and the emergency services conducted a full search. It was until after 3pm the following day that his body was found.
Like the police and Wakefield Council before him, Mr Hinchliffe issued a warning about swimming in open water.
He said: “By the time we get to this inquest we will be in the grip of winter so I warn people now not to swim in lagoons, beauty spots and lakes.
“There are all sorts of inherent dangers. If people have a desire to swim they should go to a swimming pool.
“It’s the third death I have dealt with from this site.
“It’s a very popular place for picnickers, particularly during the summer months.
“The water is extremely dangerous, although it must look very pleasant on a summer’s afternoon.
“It is extremely cold and that can have medical repercussions.
“I believe there are warning signs to this effect, advising people not to swim.”