They do single dive boats (~15min each way) which cost 90EUR including all kit, slightly less if you bring your own. I think that's quite good value for European diving.
The diving isn't great as there are not a lot of fish or anything else down there, but the water is nice and clear and the boat out to some of the dive sites is quite picturesque. For a serious diver I'd recommend 1-2 dives, but it's not a proper diving location.