Rory Golden first dived to the wreck in 2000 and left two commemorative plaques on the ship using robotic arms on the submersible he travelled in.
Five years later he returned with another plaque, this time as part of a BBC Northern Ireland documentary.
“I’ve been very lucky, the memorial plaques became my tickets,” he said. “I never thought I’d go back and five years later I was asked to take part in the documentary.”
It takes about two-and-a-half hours to travel the 4,000 metres or so to the bottom of the Atlantic Ocean.
Mr Golden and two other men were “squashed” inside a capsule just 2m in diameter within the submersible for almost 15 hours during their expedition.
“It’s cosy,” said Mr Golden. “There’s no heating inside. It goes from extremely hot on the surface and then you drop down through the ocean, it’s nearly zero degrees outside at the bottom. It’s very, very cold.”
As one travels deeper the water pressure outside the capsule reaches dangerous levels, making it physically impossible to be at that depth without the protection of the mini-sub.
“As you make your way along the bottom you slowly see this great amount of steel looming at you out of the darkness. When we got toward the wreck I saw a starfish lying on the bottom of the ocean, and then more and more. Here I was in the darkest pit of the ocean and I was looking at a creature that you would see on any beach off the coast of Ireland,” he said.
In doing these dives Mr Golden, along with his fellow divers, have joined a unique club of people who have travelled to the bottom of the ocean.
“Only 200 people have been that low down, that’s less than have been to outer space,” said Mr Golden.
Yesterday marked the 100th anniversary of the launching of the Titanic from the Harland & Wolff shipyard in Belfast.