While at the beach, I was on a bike ride with my family (on the beach, on cruiser bikes). I decided to go through a big tidal pool. It got too deep, and I lost forward momentum. Down I went, iPhone in pocket. I righted myself, immediately turned the phone to FULL OFF (from standby). Went back to the house and put it in rice for 48+ hours. Upon powering up, it had no speaker, and no microphone. Aside from that, everything worked.
I ordered the iPhone liberation kit from this site to get into the phone (had pentalobe screws from Apple). I sourced a new speaker for the phone elsewhere, as well as a new dock connector cable. Replacing those two items got my iPhone back in action, for less than the deductible on my phone insurance.
Yep. Keep the phone at home when heading to the beach. :)