Cory Nicholson, 21, died on Tuesday at Cotswold Water Park near Cirencester, Glos.
His body was pulled from the water by emergency services at about 8.50pm, seven hours after he went missing.
Relatives have described the car mechanic, from Calne, Wilts., as “a huge family man” who loved spending time with them.
In a statement they said he enjoyed “big, wide adventures of many sorts”.
Witnesses described seeing Cory “struggling in the water and shouting for help” at the water park.
Joanne Pendlebury, from Waterland Outdoor Pursuits which owns part of the lake, said the man was “looking for his missing dog”.
Two men – one aged in his 50s and the other in his 20s – jumped into the water and swam to his location “around 50m from the bank”, witness Agnes Baron said.
Tragically, they could not find him after he disappeared under the water of Lake 32 at lunchtime on Tuesday.
Underwater search teams worked well into the evening and police confirmed the man’s body had been found just before 9pm.
It is understood the park remained open and police asked people to move away from the lake while the incident was being attended to.
Earlier this month, a heroic man lost his life saving a nine-year-old girl from drowning.
Carl Storer, 21, drowned in Chasewater Reservoir after leaping into the water to save the youngster, who was fortunately pulled to safety.