Games and water activities are also unlikely to be the main destination of Porto Vecchio. As a nice bonus, though, you can still try out some of them.
For example, the lagoon waters of popular St. Julia Beach are perfect for windsurfing, wakeboarding or wakesurfing.
Hire a boat, learn to windsurf or kayak at the local school Le Pinarello. You can find equipment (if you don't have your own) and an instructor. The cost of renting a windsurfing board, for example, is 15 EUR per hour, and a lesson with an instructor will cost 60 EUR.
But it's worth bearing in mind that you're unlikely to find mind-blowing waves here, so water sports are not extreme.