I ended up using this bag as my main wallet for my whole vacation. I got three of them, and one of them got damaged by some keys or something in my pocket, so I switched to one of the others. It still didn't leak, but it had little bumps on it like the plastic was stretched. Nothing ever got wet in any of these bags the whole trip. I was careful to seal it properly every time, and I didn't get sand in it. It was just big enough to hold my passport, some cash, atm receipts, etc. Now that I've tried them, I'll probably get more in some of the larger sizes. Just as convenient as my usual zip-lock bags, but way more durable.