I love the beach, except for the lack of and/or long walk to the toilets when one has to do the inevitable.
I think females have an advantage here as they can pee more discreetly just by sitting in the sand and letting it go through their swimsuit, especially if it's already wet. As a guy, it's harder. If it's not crowded I'll sit on the sand, point my pee-thing down the leg of my shorts but not out so it's not visible, and let it out slowly as to not make a visible stream.
If there's a lot of people around I'll either make the long trip to the toilets, or pee in the ocean or lake