It's a 10k river swim along the River Dart in South Devon. Done it before, it's a really great event, very friendly, more of a social swim, although it is timed and people do race. Lots of people do as it's just nice event with a great atmosphere, and you get to swim down a river that you wouldn't normally be able to. Excellent safety cover as well. Run by enthusiasts, for enthusiasts.
It'd be nice to see a few others on here having a go.
Entries open on Tuesday 18th at 7pm, and if you're interested get signed up sharpish. Last year it sold out within 48hrs, and I missed out.
What a lovely event. Sadly, for me, it clashes with Weymouth Challenge Triathlon - I'm working, not competing, but marshals often fit an open water swim into the schedule of preparation / clear up.