Skinny Dipping Spot:

There is just a short walk of 5m from the car park to the beach. It is not a nudist beach and will be busy with families and dog walkers most of the time. So you either have to go for a quick skinny dip first thing or just before the sunsets. 
The tide goes out almost all the way to Fife (or so it seems) at low tide so.... take a camping chair to put your clothes on. No one will see you at the shore line when the tide is all the way out - especially as the sun is setting as you'll be silhouetted. However, it does remain very shallow until about 50m out so you may need to wade in quite a distance before you can swim. 

Best Time To Go:

Just before sunset.... any time of year. Especially at low tide as you can walk quite far out and away from any dog walkers. Also, because the car park leads directly to the beach it is amazing to run from there naked into the sea at high-tide when the rain is lashing down - Check the Tide Times.

Safety:

The water can get quite rough on windy days so just take care. There are a lot of hidden rocks.. so stay in the middle area of the beach. Just watch for jelly-fish in the summer... though there really aren't many to worry about. Be aware that the tide will return in quickly and may engulf your clothes... 
The water is fairly clean... but there are 2 sewage pipes going into the water (see sewage pipes map)

Recommended Links:

Edinburgh Skinny Dipping Stories facebook group

Photographs

Cheeky Skinny Dipping Photos