The beaches, of course, cannot be called really good in Sochi. Especially in the center of Sochi. The beaches are pebbly, "decorated" with ugly breakwaters, but vacationers have to be content with what they have.
Along the coast (near the beaches) there is a good promenade (pedestrian zone). As elsewhere in such places, there are many restaurants and cafes, including those with terraces. You can sit, eat, drink coffee, wine or beer and look at the sea. Or just take a walk (if the weather is good).
In the photo: Primorsky beach - one of the central beaches of Sochi. Ahead is the beach "Mayak", and further - the Sea Station of Sochi.