When I was a conservation officer, one of the items on the training agenda was water survival while wearing waders and/or hip boots, both with and without a PFD. Fortunately, the only time I had to swim while wearing either was in a nice warm pool during this training.
If you raise your knees while floating on your back, or raise your feet while floating on your stomach, the waders will trap enough air to actually help you stay afloat, or at least not be a hindrance to flotation.
If the waders fill with water, you can still tread water and float, as they become neutrally bouyant. Swimming becomes more difficult, slower and more tiring, but is definitely possible. Climbing out of the water with waders full is significantly more difficult due to the weight of the water. As stated above, a belt worn outside the waders will help to retain air.
Rough water would make it less fun...and panic could be fatal, but if you keep your head, you have a good chance to survive. Wearing a PFD makes a big difference, of course.
Last edited by wildhobbybobby; 02/06/12.
