Why not? Seems like everyone does something weird in a marathon these days... Tow a car, carry a washing machine, a tree, a child. Why not swim one?
I live on the beautiful Sunshine Coast in Queensland, Australia. This is where Australians come to holiday. It's gorgeous. Not too busy, great beaches and a long stretch from Mooloolaba to Noosa that perfectly works out at about a marathon! These are two iconic beaches with 42km or more beaches in between. Perfect! And luckily, I only breathe to my left so I get to see the coast the entire way up.
Last year we swam to half way but stopped because the conditions were so rough, it was getting too dangerous. That, and the fact that I was getting stung by blue bottles every 5mins. Those things hurt! Check out the video. This was so EPIC! Thanks to Janelle McKosker for the video.