We received a free passholder lanyard at AK a few years ago, and attached to it was a plastic ziploc-type holder for our annual passes. It is waterproof enough for me, but I am not a big swimmer. I get in the pool, and do the family raft ride and a few others at BB and TL, but I rarely swim as much as my kids do. Unfortunately, I have over-stuffed my small holder to the point that I will definitely need a new one soon, and I haven't found any that are the same dimensions, although I really liked the inexpensive ones on the REI website. They would definitely work, and I have heard that Wal-mart sells similar ones, but I have never seen them there. The bigger cases seemed a little bulky to me.