OK - not that the act of protecting oneself from the sun is a modest act, but it uses the same type of clothing. Check out this site I just came across: www.Coolibar.com - specializing in sun protective clothing and accessories, for men, women and children. They're having an end of summer sale.
You might think that the "burqini" was a silly idea. Or some of those modest suits that Christian ladies make and sell online (like wholesomewear.com or modest-swimwear.com) too. But these suit styles are also sold and worn by non-Christian and non-religious people, to care for their bodies. Maybe we need to get over our preconceived ideas about what we can bike, walk, work out, garden or swim in.
You might think that this site is "too expensive". Not everyone shops at the Goodwill only, and will find these prices reasonable. If you do - like I do - shop mostly at resale stores, you might not get to buy one of these for a while. I wonder if a really active outdoorsman or woman would consider something like this a good investment, like purchasing a good quality pair of shoes. "You just can't skimp on your health" (grin).
I don't work for these guys and they're not paying me. (If they would just give me some free samples...) Just wanted you all to be aware of what's out there.
They even have swimming skirts. :)