The Forty Foot has been my second home in Summer for many many years. It traditionally was a men's bathing place but now it is open to everyone. You will occasionally see naked older men swimming, but at busy times they usually swim around the other side of the fort, away from the main bathing area.
It's my favourite place to go swimming, but it's not for weak or nervous swimmers. You are out of your depth the whole time and the place does not have lifeguards, but the view from the water along the coast is one of the best in Dublin. If you are a confident swimmer, you can swim out and around the point to Sandycove Harbour in about 8 minutes depending on the tide.
The first thing is that yes, it is usually pretty cold. I am reliably informed James Joyce had it pretty spot on when he described it as "scrotumtightening". It's not actually forty foot deep (the forty foot thing comes from the fact that twenty soldiers used to be stationed there) but it is pretty deep so it doesn't warm up a lot even in summer.
The second thing is DON'T DIVE. Yes, you will see loads of people diving off the rocks, but this is where that old saying 'if everyone was jumping off a cliff, would you do it?' comes in. There are loads of underwater rocks, and a few people who are permanently paralyzed from them.
The third thing is it's a good idea to keep your things on the side of the changing area visible when you come in. Have had one unpleasant (non-theft) incident with my bag there.
The area is maintained by a local bathing club who run on donations so do bring a few coins if you come by on a summer day and enjoy! read more