For a lesser known place to go and relax, there is a rocky area by the sea in the old town. Walk up past the old school apparently an old school anyway and over the car park and follow a little path down to the sea. There you can sunbathe on the rocks, swim in the sea or jump/dive off the rocks some are quite high! if you are feeling a little more adventurous. The sea is quite deep here and can be a little rough at times so make sure you take this into consideration if you are not a fairly strong swimmer.If you are into extreme sports, you can try Quad Bike safari near Sozopol - around the village of Marinka. (http://atvbourgas-phquads.com)
Apollonia Festival of Arts
In the beginning of September the city hosts the well-known Apollonia Festival of Arts (http://www.apollonia.bg/en).