The Sea to Summit Big River Dry bag combines the durability of a heavy-duty river rafting dry bag while keeping the lightweight and compressible profile of a dry sack. Waterproof, double stitched, reinforced, tape-sealed seams will keep contents dry in any wet situation where the bag is not submerged. Great as a travel organizer because the nylon material won't get caught on the inside of your pack like other rubbery dry bags when inserting or removing them. Plus, the Hypalon® lash loops are perfect for hooking it to the outside of your bag if you need extra space. The Big River comes in a range of sizes, but I've found the 8L size to be adequate for all my electronics and valuables. If you're bringing more than just a cell phone and camera opt for the 35L.
Tip: No matter how waterproof a bag is, moisture is bound to make it inside eventually. To help negate the chances of this moisture from ruining my electronics I keep a few Silica gel packets in both my dry bag and my main bag where I keep my valuables. You likely already have some lying around the house or you can pick them up super cheap on Amazon.