Ok, the phone issue came up when I went to Bonaire last year for the first time. Since the wife and I were diving alone in a rental truck, I wanted to be able to make a call in case of emergency with the truck or dive injury (wife does not drive stick). Some sites are out of the way and I could not imagine my wife walking miles by herself in search of a phone or help. I took an old iPhone 6, installed Waze and some other apps and kept it in a ziplock bag in a small pelican case in my BC on every dive. We had GPS and cell service the entire trip (AT&T per day International calling). Well worth the effort and I figured if the phone got toasted, so be it. I plan on doing the same when we return this winter.
Money is in a zipped bathing suit pocket and gets wet as do the keys. I also keep waterproof copies of our passports, my driver's license and a credit card in a zipped BC pocket. Better safe than sorry.
We brought crappy sunglasses, t-shirts and old towels to leave in the truck. I wear my booties between dives all day. Frozen bottles of water for drinking and rinsing camera as well.
This method worked very well for us and having Waze GPS app on the phone was really helpful.
