Fenix 5 Plus open water inaccuracy

Former Member
Former Member
My new Fenix 5 Plus is very in accurate in open water. First time I did around 1,500 meters but it just showed 250. Second time I did around 2,500-3,000 but it just showed 1,500. However the map seemed to track what I did correctly. Also, I had 1,000 meters alerts on but instead it gave me 500 meters alerts. Data recording was set at "every second" mode and I tried all three GPS modes. I also have version 4.20. First reply from Garmin Spain was: "GPS measurement in open water will never be as accurate as when running or cycling because GPS looses connexion when paddling, so we don't think your watch has any problem". Anyone else?. Not surprisingly, the Fenix 5x Plus is also having open water issues.
  • Same Problems with Fenix 5. seems to be the same bad software. Is there and Data Know-how when Garmin fixes this. Betöre GPS Update the Fenix wirkend Fine. So it seems to be possible
  • 920XT user. I knew it wasn't giving me an accurate reading but until IMNZ I didn't realise how inaccurate. I stay away from the race line, so swim more than the 3.8k, but apparently I only swam 3416m. That to me is totally unacceptable.
    Like the idea of attaching to the goggles and will give that a go next time. Didn't feel comfortable with the Garmin suggestion of placing in my hat as I have had these split before.
  • Like the idea of attaching to the goggles and will give that a go next time. Didn't feel comfortable with the Garmin suggestion of placing in my hat as I have had these split before.


    Goggles have been knocked of my face in the past...

  • You can use these (or similar) as a headband under the swim hat - http://gotchastraps.co.nz
  • Perhaps I'm blessed by low expectations, or perhaps my watch for whatever reason has better GPS reception, but I did my first OWS last weekend and, knock on wood, it was pretty good. I had one inaccurate hitch in my track when I loaded the data in GC, but other than that, it was pretty spot on. Even showing my drift towards shore before I stood up, walked out, and corrected my angle for the waves I was swimming in.

    I was actually pleasantly surprised by the performance. (note this is a Fenix 5 Plus, SW version 6.0.0.0 and I believe GPS 2.3)ciq.forums.garmin.com/.../1466685.jpg
  • I had my first OWS with a Fenix5 (3 swims) got it for Xmas and have not used it until the IMPR703. My previous watch was a 920XT. That gave very good, consistent quality of OWS results. My Fenix5 bounces all over the place and I get crazy lines and much more yardage.

    When I look at the output, it feels like they could easily fix this issue with software that smooths out the lines by removing obvious outlier GPS points. In the first swim shown below you can see the one major goof where it lost me when we swam under a bridge, but also the zig zagging in the main swim was caused by a few outlier points. In the recovery swim I swam in a triangle from buoy to buoy but it has me all over the place. In both swims I did not stop.

    https://connect.garmin.com/modern/activity/3471374842 (Race)

    https://connect.garmin.com/modern/activity/3473071688 (Recovery)
  • Have registered my first OW swim with the 5+ (only start of spring here in UK :) water temperature 11.7C which is pretty good for this time of year but still freezes your face for the fisrt 5 minutes) - despite having GPS lock and starting the watch at that point the watch did not start recording a GPS track for about 50 metres. The track then took me straight through the middle of an island. After that the track settled down to a reasonable approximation of my route - will see how this goes over the next few swims - I am on beta 6.62
  • Not much to add really. I've been swimming with a 5+ in the sea since the end of October with mixed results. Sometimes it gets it, sometimes it dioesn't. On occasion, it'll start recording for a couple of 100m then stop. If I then stop and allow it to ‘catch up’ it'll straight line from where it lost it to where I stopped then generally record most of the swim. But then sometimes it'll have an ‘off body’ experience and record something entirely different from where I've swum. I do know Garmin are working to resolve this. I'm guessing the advent of the northern swimming season will concentrate minds a little more.

    BTW, water temp here is still around 20C but it is heading south. And it's dark!
  • DC Rainmaker had some pretty positive sounding comments about OWS on the MARQ he's testing. Don't know if that's down to firmware improvements or that the new watch is using the Sony GPS chipset. Given the problems Suunto has had with the Sony chip I wouldn't say that it's wholly down to the new chip being superior.