The experienced diver, understood to be Josh Bratchley, a meteorologist, failed to return after entering a cave in Jackson County, Tennessee, on Tuesday.
A search and rescue operation involving emergency services and expert divers from the US was launched after his group raised the alarm in the early hours of Wednesday morning local time.
Chattanooga Hamilton County Rescue Service, whose experts had been assisting with the operation, said on Facebook: "The diver was located and brought out of the cave by rescue divers! All are safe on the surface."
Earlier, Bill Whitehouse, vice chairman of the British Cave Rescue Council, told the Press Association: "There's a British cave diver who is overdue on a dive in a cave in Tennessee, a place called Mill Pond Cave, Flynn Creek, in Gainsboro.
"He went in on Tuesday on, I understand, a dive to replace a guideline in the flooded section of the cave and he didn't return from that mission.
"A couple of others there went in to look for him and weren't able to find him. When they weren't able to find him, they came out and they raised the alarm."
Expert divers from Arkansas and Florida are understood to have travelled to the site to assist in the rescue mission.
They were thought to be preparing to enter the cave at around 6pm local time (midnight Wednesday).
"Cave diving is not something to be undertaken lightly, so they would need to feel fit and able," Mr Whitehouse said.