Avoid pressing the keys under water.

Is it safe to press the buttons while still wet but above water surface?

Should be safe.

woudn't the water just leak the same as the button is still wet?

No, because there is no pressure.

Is it that complex/expensive to design a watch with watertight buttons that could be pressed while at 0,5m deep?

Obviously it's a challenge.

I agree with tmk2 - inevitably there is water between the button and seal. Mine sometimes drains out hours later. But the button press puts slight stress on the seals, as does water submersion. It is unlikely to cause a leak doing it just once or twice by accident. But over repeated exposures (as evidenced by posts with leaks with the owners not being aware of this caution), it could leak. I use the countdown timer to avoid the awkward push button while trying to push off quickly routine. Also don't forget to rinse with cold water after each swim. Personally I would not shower with it, but that is my own subjective belief (backed by understanding of what heat does to materials) and I know others disagree and do so without problems.

I've pressed the buttons underwater for years, mind you it's about 1 foot under water at the end of swim sets. I've gone cliff jumping, wakeboarding, waterskiing, sailing, all with the watch on and have never had any issues across the 3, 3hr and now my 5.

You may be lucky. A lot of posts from people whose watches have leaked have indicated that they were not aware of this caution in the manual. Of course this only proves correlation, not causation, but you figure that when the manufacturer advises us not to do something that will only get us to buy a new watch, they likely know something we don't. ;)

Sorry but people need to stop being idiots and until they do, stop feeling entitled to whine and complain. I am referring to "that they were not aware of this caution in the manual".
If you buy a $500 device, read the manual. If you don't like the design, read it BEFORE you buy and if you do not like what's in it, buy a Casio. If you don't read the manual and take a risk, then don't complain to the manufacturer (there was another guy in this forum complaining the watch temperature sensor stopped working after wearing the watch to sauna).

If enough people don't buy the device because of a "design flaw", Garmin will notice and fix it.

Apologies for the rant.

I agree people should read the manual, and if they don't like the limitations, don't buy it. I think it is reasonable though for the OP to question why it would not leak just wet, and to wonder why you don't get more for $500. But in the end, as I tell my daughter, "you get what you get, and you don't get upset." ;)

I've had four 935s all failed through temperature sensor failures after about 3-4 months. Garmin has replaced them all for free and this time I'm getting a Fenix 5S 47mm in hopes that it is more durable. I do not believe that the temperature sensor failure is due to leaking buttons and I find it appalling that Garmin would sell a high-end multi-sport watch claimed to be waterproof to 50m that has leaky buttons. I think it actually shows defective design and product development and testing. Also, they have not actually done anything to fix the problem. Instead they put something on their website (not in the manual) that says: don't press the buttons in the water on this watch that we say is waterproof.

Instead they put something on their website (not in the manual) that says: don't press the buttons in the water on this watch that we say is waterproof.

Page 28 of the FR935 manual.

https://static.garmin.com/pumac/Forerunner935_OM_EN.pdf

Also, Garmin never said your 935 was waterproof.

https://support.garmin.com/en-US/?fa...oof&tab=topics

Your statements are incorrect.

It would be very interesting to know the statistics on the 935s and Fenix 5's (all types) for failures of all types. I was swimming with my nephew over Christmas. We both used 935s and mine then had a functioning temperature sensor. He was interested in a screen that showed temperature (he never had checked) and sure enough his temperature sensor was dead. About a week after this workout my 935 temperature sensor died (as reported in the post above on 28 December).

Garmin sent me a Fenix 5 (not an S as promised by Garmin) as a replacement and it was a refurbed unit. It died with a black screen after two weeks of use! Garmin is now shipping me a new 935 as a replacement for the Fenix 5.

Taking the admonitions of others to heart I've thought about my use of the device in the water, shower, etc. and believe I rarely and inadvertently pressed the button under water. I doubtless pressed the buttons out of the water when the device was wet during swim workouts. With the replacement 935 I plan to never, ever press buttons again with a wet watch and especially avoid pressing the buttons under water to hopefully preserve the watch but also as a test. I'm using the watch for running and swimming and as as a wristwatch. I don't believe I've used it in any way that is contraindicated by the manual and haven't exposed it to any extreme environments either on my wrist or off. But I've either been very unlucky or I've done something that compromises the watch or it is a defective design or an uneven manufacturing process.

I don't accept the idea that water tight (or proof) buttons are too much of an engineering challenge or cost issue to include in a $500 watch. I'm wearing a $50 Casio sports watch while I wait for the replacement that I've had for probably 15 years using it exactly as I treated the 935s and Fenix 5 and it has never failed. I have replaced the Casio battery which requires removing the rear plate and exposing the guts of the watch and restoring the seal (a very simple gasket) and it has never failed. I looked at the Casio button design the last time I did this and the design and implementation is butt-simple. The Casio claims 200m water rating which is about 20 atmospheres but the 935 is supposed to be good to 5 atmospheres so it's hard for me to believe that they wouldn't have included buttons with water integrity considering how easy and cheap decent under water buttons actually are.

However, I take your point that the manual forbids pressing the buttons in the water and I plan in future to avoid that entirely! To me an obvious design defect and it has to be a constant drain on their support resources and replacement process. Imagine if Apple had an iPhone with a defect like this! And they did. I had an iPhone 6 Plus which had a defective motherboard connector internally that failed after the case was flexed too many times. They replaced three of my 6 Pluses and obviously had figured out design and manufacturing changes by the time I got the last one which is still working fine after a number of years. So it baffles me why Garmin wouldn't address this issue in a premium watch.

I have looked at alternative devices (like Suunto) but none of them have the functionality of the 935 for my purpose. So I'm sticking with the 935 as long as Garmin continues to replace them if they fail. I'm getting very efficient at setting up new ones :)

Casio G Shock watches have a double O Ring setup on the pushers and while you may have enjoyed using them underwater, even at 200m WR, it states in the Casio manual that you shouldn’t operate the buttons underwater. The only Casio watch that allows this is their Frogman series which have an ISO rating of 6425. Coincidentally, the Suunto lineup (like the Suunto 9) have an ISO rating of 6425. That said, they’re not meant for diving like the Frogman.

It would be interesting to see the comparison (or explosion) for the Descent Mk1 and the Fenix 5x series to see the hardware difference since the Mk1 can be used underwater.