As other reviewers have said, I wouldn't trust my phone, camera, or cigarettes in this bag without them also being in a ziplock baggy.

The bag is watertight by folding it over a few times and then using two small straps to hold it in place.  It didn't get any water in it during our ride down the lazy river, but it got a little water in it on the river rapids raft ride.

Its better than just a regular fanny pack because I wouldn't trust my phone to just a ziplock in a regular fanny pack but always take extra precautions.