A waterproof snorkeling bag is a really useful tool for protecting your valuables from theft. It is not a good idea to leave your keys, money, ID or cell phone on the beach or in your car parked at a beach. More and more beaches are having problems with car break-ins. Strap on a waterproof waist pack and you don't have to worry about it.
We have used a waterproof box with a waist strap for years whenever we are in public areas and entering the water from the beach.
These are the things we keep in our waterproof case:
Just the small important stuff. We don't worry about our snorkel gear bag, towels, clothes, sunglasses, etc.
We are fortunate that we haven't had anything stolen on a trip. Using a waterproof snorkeling bag is probably one of the reasons we have been lucky. We highly recommend them for your peace of mind. Because when we are away from home if any of those things got stolen it would really waste a lot of our travel time. We much prefer to take our valuables with us like this rather than leave them in the car or hotel.
So there are a variety of products you can use to do this. None of these products are perfect, but we have found that hard boxes or cases are more consistently waterproof. The seals are not flexible so are less likely to leak.
These are plastic bags with some sort of waterproof seal at one end. Don't be tempted to use what is called a dry bag. The waterproof closure is made by folding over the top several times and attaching some sort of clip (or velcroing it down). These are not waterproof if dunked and they are bulky.
Get a bag that has a simple and secure waterproofing clamp at the top, like the ones made by Aquapac. The best sized model for snorkeling is the Aquapac Beltpac Waterproof Snorkeling Bag. It is the ideal size for passports, money, cell phones, etc.
Another brand that has a belt pack is OverBoard. It is called the OverBoard Waterproof Pro-Sport Belt Pack.
Here are a couple more options with smaller pouches.
The OverBoard one has a strap that you wear around your arm, it is called OverBoard Waterproof Pro-Sport Arm Pack.
Aquapac also makes a smaller pouch sized for keys, money and ID, called the Keymaster. You carry this with a neck lanyard.
Here are a couple options of waterproof snorkeling bags made specifically for phones.
Kwik Tek makes a waterproof cell phone pouch called the DRY PAK.
OverBoard offers a Large Waterproof Phone Case.
This is what we use (pictured on the top of the page) and recommend over a bag, because it is very reliable and fits two passports, a wallet, keys, an iPod and a cell phone. But if you only have keys, some ID and money, we would consider one of the well-reviewed bags above.
Waterproof boxes are proving to be more challenging to find. Of course there are always Pelican Boxes, but they are only rated water-resistant, which is not good enough, especially if you dive down at all while snorkeling. And our favorite brand of underwater boxes, Otterbox, seems to be discontinuing the line.
There are three things these boxes have that make them worth recommending: the waterproofing seals are the type that have worked for us on our waterproof boxes and camera housings; they have loops on them so you can easily and securely strap them to your belt while snorkeling; and they have clear top options which is nice so that you can see if there is a leak.
Here is another product you can use to keep your valuables with you while snorkeling. It attaches to you by a belt and floats on the water behind you. Because of its bright color, it doubles as a dive flag. You should not dive down with one of these attached to you.
There are 2 compartments, one that fills with air so that it floats, and one for stashing your valuables.
New Wave Swim Buoys come in 4 colors, 2 sizes (15 and 20 liter), and are made out of 2 different materials, PVC and TPU. For snorkeling the TPU is more durable and is unaffected by sunscreen oils, but only comes in orange.
Once you have your chosen bag or case, check your seals for any dirt or hair before you close your case EVERY SINGLE TIME. A tiny thing in your seal can cause a flood and your stuff is ruined.
No matter what method you choose, do this....put everything in a good quality zip-lock bag, and zip it closed, before putting it all in your waterproof snorkeling bag or box. It is very inexpensive backup plan so you won't get ruined stuff if your case or bag floods. You can also throw some silica desiccants in there to help keep moisture down.
We greatly prefer to strap one of these around our waist and wear it like a fanny pack. Putting things around your neck is not a good idea. It will hang in your way in the water and be a nuisance. The companies always have pictures of people standing on beaches with these around their necks, but that is not how we use them (we are laying down in the water).
So long as you don't get too big of a box or bag, you won't even notice it in the water. Our box floats, so Nicole (she normally wears it) says she almost never feels it. In the picture below you can just see the otter box Nicole is wearing.
If you freedive, you may want a bag instead of a box, so that you can relieve it of extra air (a floating box is a pain when diving).
If you get a box or a bag, just make sure that your waist strap is positively connected to it. We would not use the supplied belt clips that some come with. We just used a strap we found, threaded around the box loop twice (to keep it from sliding), and there you go.