An underwater mausoleum off the US coast modelled on the lost city of Atlantis is helping relatives ensure their loved ones are sleeping with the fishes.

A year after Will and Daniel Payne lost their mother and nearly two decades since their father’s death, they have helped their dying wishes come true.

Three generations of family members were present as the brothers slipped into flippers and de-fog their masks off Miami Beach.

Coral Reef Cemetery
Will Payne, right, and three generations of his family throw flowers into the sea (Wilfredo Lee/AP)

Will Payne, who became a certified scuba diver just days earlier, checked his oxygen tank and jumped into the waters to secure a concrete marker mixed with their ashes at a memorial reef about three miles out to sea.

This unusual resting place is exactly what the Paynes say their parents wanted.

Buel Payne, a former Coast Guard member, and Linda Payne, who grew up on the water and loved boating, will spend their afterlife in a memorial modelled after the lost city of Atlantis.

Their ashes will be among lion statues and ornate gates and pillars that are encrusted with sea life.

It took nearly four years for multiple government agencies to sign off on this underwater mausoleum, which is designed to encourage a healthy ecosystem.

Roughly a decade later, the Neptune Memorial Reef is home to the cremated remains of 1,500 people, and any snorkeller or scuba diver can visit.

Coral Reef Cemetery
Jim Hutslar, operations director for the Neptune Memorial Reef, affixes a cement baluster mixed with the cremated remains of Buel and Linda Payne and marked with a memorial plaque (Wilfredo Lee/AP)

The Paynes are the first to be memorialised in the reef’s expansion, which opened this summer and will make room for an additional 4,000 memorials over 16 acres, about 40 feet deep.

Placements start at around 1,500 US dollars and can go up to 8,000 dollars, with the priciest placements for specialised shapes like sea turtles and stingrays or for prominent spots throughout the city like the lions.

With reefs struggling worldwide against coral bleaching and other threats, the memorial’s builders are providing coral a head start.

The concrete structures offer a high pH level, enabling sea creatures to flourish.

“We’re seeing animals here that we haven’t seen before. Ones that have been missing for a long time,” says Jim Hutslar, the reef’s operations director and one of the founders.

“We actually found a long spine sea urchin that was considered extinct in the Caribbean Sea.”

Sara Thanner, an environmental supervisor for the Department of Regulatory and Economic Resources, says an April survey showed the reef supports more than 65 different fish, shrimp and lobster and 75 other species including sponges, soft corals, and hard corals.

For people making end-of-life plans, the reef means being part of something living.

Mr Hutslar is hoping that decades from now, the memorial will have grown into a massive coral reef where individual markers will no longer be distinguishable, and “family members will just know their loved ones are part of it.”

“We’re creating life after life,” he said.

Coral Reef Cemetery
Guide Pedro Cinta descends down a line to the Neptune Memorial Reef (Wilfredo Lee/AP)

While Mr Hutslar, Will Payne and another diver descended to the ocean floor, Daniel and his wife and three children snorkelled on the surface, gazing down through the strong clear currents.

They spotted a parrot fish, barracuda and a monster snook while abundant schools of small, colourful fish darted in and out of the sculptures.

They had picked out a small bronze headstone reading Together At Last to mark the ashes, adding their thumbprints on a decorative concrete sea shell.

Coral Reef Cemetery
A lion sculpture sits among parts for a new section of the Neptune Memorial Reef (Wilfredo Lee/AP)

The divers picked a spot amid the underwater city’s striking columns and statues.

“It’s just amazing. It’s so peaceful,” Will Payne said.

“If there is a heaven, that would be it for them.”

Back on the boat, the family ate biscuits and oranges and enjoyed a day at sea, laughing, hugging and crying at times.

The men’s aunt and uncle also brought red roses that each member of the family tossed overboard.

Coral Reef Cemetery
Will Payne, left, and his guide Pedro Cinta, right, descend down a line to the Neptune Memorial Reef (Wilfredo Lee/AP)

Daniel Payne, 41, said he plans to get scuba-certified so he can see it up close, and return every year.

“I really didn’t get it when (my mom) was telling me about it and the more and more I think about it, it’s really a nice, peaceful spot for your last resting place,” he said.

Mr Hutslar and his partners were solely focused on supporting marine life at first, figuring the cemetery would help pay for the reef.

But he has helped hundreds of families say goodbye to their loved ones over the years, giving him a calling he has come to cherish.

“This has actually become my favourite part — being with the families,” said Mr Hutslar.

Coral Reef Cemetery
Family members of Buel and Linda Payne snorkel to watch the installation of a memorial plaque for the couple (Wilfredo Lee/AP)

Memorials for children especially stick in his mind.

There is something healing about the ocean.

He says you can see it when families return to the surface.

Coral Reef Cemetery
Ray Lowenstein with Neptune Memorial Reef, gives a tour of the site (Wilfredo Lee/AP)

“You can watch something wash away,” he said.

It happened again, Mr Hutslar said, as Will Payne paid his final respects.

“I hope you’re happy where you’re at. I love you,” Will Payne whispered through his mouthpiece.

“Keep an eye on us.”