TheFork users who ate in Fontvieille have said really good things about Le Belvédère - Hôtel Belesso, La Regalido and Nancy Bourguignon - Du Côté des Olivades. Maybe you should give them a try!
Some of the more popular Swimming pool restaurants having a terrace in Fontvieille according to TheFork users include:
Le Belvédère - Hôtel Belesso, with a 8.8 rating
La Regalido, with a 7.5 rating
Nancy Bourguignon - Du Côté des Olivades, with a 9.7 rating