How reliable are waterproof phones? I want to have a waterproof phone that I can realiably wear when I am windsurfing.
During a session it might get wet and might sink for a few centimeters for a couple of seconds from time to time.
I bought a refurbished Huawei P20 Pro for the purpose, IP67 waterproof.
I had watched videos on Youtube where it would be under 1.5 meters water for 15 minutes and still be working fine.
After a short session on the water with this phone, where it got wet but never sunk, the next day the phone was dead forever with water damage.
I imagined that, being refurbished, it might have been hacked by the previous owner.
I got my money back and bought the same phone again, also refurbished.
This one was really new, in the box with all the gadgets.
I took it on a session, this time in a cheap &quot;waterproof&quot; pocket.
At the end of the session, there was some moist in the pocket.
Next day the phone was dead forever. Again.
Was this hacked too? I don't think so.
I got my money back and bought a refurbished Samsung S9, which is waterproof IP68.
Now. I am not going to bring it with me on the water until I am sure it will survive.
I could buy a IP68 protection for it but wouldn't it be overkill and actually nonsense (IP68 + IP68 = IP68) and maybe still let water in?
Are these videos on Youtube realistic?
Maybe 10 minutes after the video the phone becomes useless.
Are the IP67 and IP68 certifications reliable for general public phones?
I am sure they are when it concerns professional equipment.
Thanks for your thoughts
I have a fair amount of experience using and testing IP68 waterpoof phones.  Here are my experiences.
I personally have had quite a bit of success with them in several different types of environments.  When getting a new one, here's what I do before I put any data on it:

I charge it up and turn it on.  I make sure it works before testing.
I set the display to go off after 5 minutes.  I set an alarm with both sound and the buzzer to go on in 10 minutes.  This will ensure the speaker and buzzer work underwater, and will also provide a little agitation.
With the device turned on, I place it in a tall glass of fresh water for 30 minutes.  I want the glass to be tall to increase the water pressure.  A flower vase works well.  The device's display will shut off after 5 minutes, as expected.
With the device still wet, I turn it back on, and test it.  The speakers may temporarily sound horrible; I find this to be normal on some models.
Now, I place it under a water faucet turned up to a flow rate in which I would wash my hands.  I wash it under that pressure at all angles for several minutes and at various non-extreme temperatures.
Repeat step 4.
I let it sit overnight.
Repeat step 4.
I place it in the bottom of a tub as deep as I can, but within the manufacturer's specifications.  I try to agitate it as much as reasonably possible, often using a long stick or with a long piece of string or dental floss attached.  Then I let it sit in the water up to the duration specified by the manufacturer.
Repeat step 4.
I dry it with a cloth and vigorously shake it to remove some of the water within ports.
Repeat step 4.

I have yet to test a device that hasn't survived these basic tests.
At this point, I repeat the above steps with the type and temperature of water to which it will be exposed during real-world use.  I do this knowing that it may invalidate a weak warranty by a manufacturer that does not have confidence in their products.
I have only found a few minor downsides to waterproof devices:

Often, after being wet, the speakers sound really bad.  I typically have to wait for them to dry completely.  If I need good quality audio before then, I'll play loud music to use the air pressure created by the sound waves to help extricate the water.
Charging and data transfer are often risky/impossible until the device is completely dry.  Depending on environmental factors, this may take anywhere from 30 minutes to 12+ hours.  I've learned not to plug it in for as long as possible after being wet, to reduce fire risk or shorting a circuit.  When I do finally plug it in, I keep an eye on it, and I don't let it charge unless someone can supervise it (and therefore cannot be asleep).  I've learned to not attempt any data transfer via cable for at least a day, if I can wait.
Any ports are the hardest thing to get dry.  I haven't tried them yet, but I'm researching buying some little rubber port covers to hopefully help with this issue.  I am concerned that they will all fall out and get lost on the fist use.
It's often hard to find waterproof phones with easily replaceable batteries and microSD slots.
Repairs can be harder to perform yourself or more expensive for a technician to perform.

I have spoken to repair shops who state that they get waterproof devices that weren't nearly as waterproof as the manufacturer claimed.  Because of this warning, I tend not to intentionally push the limits of the waterproofness once the device has data on it.  Remember that increasing water pressure due to turbulence is similar to increasing water pressure due to depth.
If I'm going to be in extreme conditions, I place my waterproof phone inside a clear waterproof bag (which also has a rugged lanyard, which I have reinforced).
Overall, I highly recommend waterproof devices.  Just test them well before use, and make sure you backup your data frequently.  As we say in rock climbing, &quot;never climb higher than you are willing to fall&quot;.
If you do have to return a device due to a waterproofing failure, please do your best to ensure the manufacturer doesn't just offload it to a refurbisher who will then sell it to an unsuspecting person who will not be aware of the device's previous failures.  No one wants that to happen to them, so let's work together to make sure it doesn't happen to others.