I purchased this backpack/dry-bag for trip that I took to Vieques Island, Puerto Rico. Many of the Vieques travel websites discourage people from leaving valuables in their Jeeps while at the beach; they also discourage folks from leaving valuables on the shore while they're in the water ("petty theft" is common in Vieques). I go everywhere with my DSLR camera and wanted to be able to bring it to the beaches in Vieques, so I thought that this bag would be a good option. I wore it on my back while I was snorkeling and swimming at the beaches. The backpack was splashed but was never submersed; there was a little water (not enough to damage my camera) in the bag every time I used it. If I use it again I'm going to purchase a conventional dry-bag to put inside of this backpack. I'm also considering trying the SealLine Urban Backpack, but it got mediocre reviews and is more expensive than the Dakine pack, so I'm not so sure about that option.