British billionaire and adventurer Richard Branson may have lost his unwritten race to the bottom of the ocean with James Cameron, but he told AFP Monday he wants to team up with the Hollywood director. Branson congratulated Cameron on making the solo submarine dive into the Mariana Trench, the deepest spot in the world, earlier Monday. \"It\'s incredible what he achieved today,\" Branson said in a telephone interview from his private Caribbean retreat, Necker Island. The director of \"Avatar\" and \"Titanic\" is now the leading man in a rarefied race among entrepreneurs and explorers to get to the world\'s almost entirely unexplored ocean beds. The Mariana had only been reached once before in a brief visit by a two-man crew in 1960. Branson\'s team has also been planning to visit the Mariana, as part of a mission to reach the deepest spots in each of the Earth\'s five oceans. But Branson is not far behind Cameron in the race to the bottom. His Virgin Oceanic submarine, an airplane-like vehicle that would not look out of place in a James Bond film, will undergo final pressure testing before taking Branson later this year to the bottom of the Atlantic, in the Puerto Rico Trench. That won\'t be as deep as the approximately 36,000 feet, or 11,000 meters, that Cameron\'s Deepsea Challenger reached in the Pacific. But it\'s never been explored by a manned submersible and is a landmark in the world\'s most mysterious terrain. \"Nobody in the Atlantic has been further down,\" Branson said, \"and the Puerto Rico Trench is nearly 30,000 feet (8,600 meters), deeper than Everest is high.\" The founder of the Virgin business empire said he\'s also looking forward to pairing his craft with Cameron\'s more torpedo-like submarine. \"It\'s quite possible we might put the two submarines together and explore different parts of the oceans,\" Branson said. \"They\'re the only two submarines in the world capable of going below 18,000 feet.\" The difference, he said, is that Cameron\'s performs better on the dive and carries more film and other equipment, whereas his comparatively lightly built Virgin Oceanic is best suited to exploring once submerged. \"Ours can go quite big distances at the bottom of the ocean,\" he said, looking forward to uncovering Spanish galleons or \"a species that hasn\'t been discovered.\"