Although I did say that a disposable lens could be discarded if you get water in your eyes to prevent possible infection, I should have noted that this has never happened to me and I snorkel a lot and also dive from time to time. Also, I've never lost a contact when snorkeling or diving. In fact, I've never gotten water in my eyes or lost a lens with swim goggles, under which I also wear contacts. It is possible, however, so knowing that you wouldn't be out a lot of money if it did happen is comforting. I always bring spares just to be safe.