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RickyDee said..
I keep my car keys in an Aquapac - I've had one for years and it works really well. They do have sizes that can take a phone. They are waterproof to 5m depth, so fine for kiting.
Just so you guys know and to save you having to buy a new phone. When something its rated to say 5m waterproof that's not, "if I crash my kite and the phone hits the water as long as I don't go below 5 meters ill be fine" because that is not how it works....
That 5 meters is simply a pressure rating so what it is saying is under ideal conditions you can take that waterproof pouch 5 meters under water without any additional forces on it.
roh x g x h Pressure under 5 meters of water is 1000 x 9.81 x 5 = 49050Pa
Now assume you are 75kg and you fell from a height of half a meter onto your phone.
E=M x g x h 75 x 9.81 x 0.5 =367.9
F = E/s 367.9/0.5 = 735.75N
Now P= F/A Assume the phone case is 10 cm by 5 cm so area is 0.005 m^2
P= 735.75/0.005 = 147150 Pa
147150 / 49050 = 3 therefore if you weighed 75kg and you fell half a meter onto your phone in its 5m waterproof case you would exceed the limit of the case and would in fact need something rated to 15m waterproof, but thats only half a meter. If you were to also factor in how fast you were going laterally you would need something really waterproof.
I found this out the hard way when I went wake boarding with a camera waterproof to 10 meters. One big stack later and I wondered why it didn't turn on.