The former president got to do some kitesurfing, an activity his security detail probably wouldn't have allowed during his eight years running the country.
On his Virgin blog, Branson recounted a story Obama told him about how he missied surfing:
"(J)ust before he became President, he had been surfing on a dangerous break in Hawaii. When he came in from an exhilarating session, the new head of his security team turned to him and said: 'This will be the last time you surf for eight years.' For the next eight years he didn't have the chance to surf, enjoy watersports or do many of the things he loved."
Branson, the British founder of the Virgin Group, described Obama's exploits in a post on his company's website, explaining that he challenged the former president to learn to kitesurf.
Kitesurfing is a cross between surfing and flying a kite, in which the surfer allows his or herself to be pulled on a board across a body of water.
Branson said he wanted to introduce Obama to kitesurfing, while he himself had wanted to learn foil-boarding, so they set up a friendly challenge to see who could learn his sport more quickly.
"Barack started learning to kitesurf on the beach on Necker for two days solid, picking up the basics and flying a kite as if going back to being a child again. Then he went into the water, standing up and getting a feel for the kite. Finally, he put the board at his feet and gave it a go. Being the former president of America, there was lots of security around, but Barack was able to really relax and get into it," Branson said.
Branson said both men fell many times during their learning processes.
"We were neck and neck until the last run on the last day, when I got up on the foilboard and screamed along for over 50 metres, three feet above the water. I was feeling very pleased with myself, only to look over and see Barack go 100 metres on his kiteboard! I had to doff my cap to him and celebrate his victory," Branson said.