Louise Cardwell: Swimming has been permitted in this fantastic, beautiful, fresh water Loch since 2007.
It is the main reservoir for the supply of fresh water to Glasgow and as such, offers fabulous, clear water which is a pleasure to swim in. There is no fishing permitted either from boats or the shore, so there is no risk of angler's lines (or their tongues!).
Park at the main Loch Katrine car park off the A821 (a pay-and-display car park so remember some change). Walk or cycle along the access road on the North shore of the Loch. After about a mile, there are many good access points to the water for swimming from all the small pebble beaches.
Two cruise boats provide tours up the and down the Loch, mainly staying to the centre of the Loch and South shoreline.
Holly Waters: A popular loch for cyclists. As noted, 2 pleasure boats regularly go up and down. 1.5 miles from the jetty, going anticlockwise round the loch there is a good small beach. Quite sheltered/private, and it is clear that passing cyclists, though you can see them, are unlikely to notice you. There is a 'bridge' with a small plaque telling you the distance just by the path down to the shore.
No hazards I can see at this spot as described.