Adam Walker is a British man swimming the hardest 7 oceans of the world. He'll be the first Brit to do it. Only four other people have completed the feat so far. This video shows him swimming the Cook Strait, between the two islands of New Zealand. He was accompanied for more than an hour by a pod of dolphins.
His next and final swim will be in the Irish Sea in August.
Only advice I'd have: make sure those fins are dolphins. Not sharks.