During recent years and after the change in the law, scuba diving has had an explosion in popularity on Thassos and you can find several dive schools dotted around the island. All are professionally run and offer facilities for the complete novice right up until professional diver levels.
Try your luck at fishing, there are a few well organised trips available or simply find a nice spot on the shore and see what lady luck brings!
For those seeking physical challenges there are the annual Thassos Mountain Marathon and various mountain and road bicycle competitions. Not for the faint-hearted.
Of course with a super beaches you will find beach volley just about everywhere, and during the summer season there are also several organised competitions.