If you knew how cold the water is on these latitudes you'd not be as upset about the "beach" part.
Anyways, I think it's a good idea, for the right convicts. If they feel society cares about them and values them, maybe they'll be encouraged to become nice productive members of society once they get out. Treat people like scum and they become scum.
By the way, here's their webpage. It's in Norwegian, but it's got some nice pictures.
http://www.bastoyfengsel.no/