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If I were you I wouldn't try to house your iPhone for snorkeling pics. I think you'll be disappointed with the quality OR you'll be frustrated with the functionality of the better quality cases while in the water.

If this is only for this trip then go get a GoPro Hero 3 Black $400 and when you get back you can easily sell it for at least $300. This is the ballpark of a good waterproof case for the iPhone. The quality of the video and pics is outstanding with these underwater. These are your honeymoon pics don't forget.

With that said I do use this at the beach to keep my iPhone safe. I take it in the pool too but I wouldn't think of capturing nice memories with it.

http://www.rei.com/product/850899/e-case-iseries-case-iphone
 
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