Even if I do a pre-dive toilet visit, I ALWAYS end up with a full bladder by the end of the dive. The problem for me is that I actually find it very hard to pee when I'm in the water, even if the need is great... it takes concentration, patience and most importantly a place to keep sort of still. The easiest way for me is to hang onto the ladder and stop moving. I have to really squeeze my abdominal muscles to force the urine out. I then "flush" by pulling the neck of my wetsuit out and letting the sea water flow in. It's not always practical to hang off the ladder, though, so it's usually a matter of doing it once back on board the boat. Fortunately for me, our boats in Phuket all have toilets But unfortunately, the issue then becomes one of stripping down fast enough

Most drysuit diving women I know just use adult incontinence pads (Depends).