Open Water Swim performance

Has anyone had any open water swim experience with this watch yet?

Two questions:

  • How was the accuracy of the tracking?  How does it compare with 935 or 945?
  • Does Livetrack over LTE work during open water swim?



  • I don't do open water swimming so I can't comment on the performance, but I checked the activity on the watch and it does support LTE LiveTrack.

  • I often swim an out and back course 1-2x per week and had really poor results last year with my 935.  I think the main reason was that I often loop back 100-200 yds to a slower swimmer every ~500 yds or so or make strange corners to add yards due to our speed difference.  The 935, for me, does "ok" on straight lines but struggles with turns as the number of points it records is so low it nearly always cuts distance.

    Yesterday I received my 945 LTE, but only after my swim so I will need to get back to you on results, but leaving a Vivoactive HR in my swim buoy my 935 recorded about 400 yds short (real course was about 1900 yds, it recorded under 1500).  This is pretty consistent with what I see with this usage on the 935 so will be eager to see how the 945 handles my routes.

    Sorry to waste the reply, but I should have some result by the end of next week if not sooner.

  • Interesting to hear your experiences with the other devices.  I have a 935 as well, and have mixed results over different firmware versions.  Right now it's OK, but clearly not great.  Just want to make sure it's not a complete disaster before upgrading my 935, which is on it's last legs

    I'm looking forward to hearing more, once you get a chance to get out there.

  • My only swim so far with the 945 LTE looks really impressive to me (coming from the 935).  I swam in the same lake I usually swim in, but this time gave it quite the test (in my mind).  Typically I swim a ~750 yd straight swim across, but have a few small loop-backs to another swimmer swimming with me but a little slower.  The 935 generally misses the loop backs or extra corners badly in my use.

    Example 935 track vs Buoy GPS from Tuesday (935 short by 450 yds):

    Today I swam with a different group and did smaller random loops - so this gave many shorter straight shots with more turnarounds and random corners.  I didn't have my 935 on me, but I suspect it would have struggled given past experience (2x a week swims with the 935 all summer last year).  The 945 LTE track looks pretty good and is within 120 yds of my buoy GPS distance (over the same ~1850 yds total).  Honestly being that close on this shape of course is surprising to me.

    I will probably swim "my old way" again in the next week or so and report back at that time...


  • One more data point - I got another swim in in my "normal" routine from last year.  The 945LTE showed me the best match to my buoy that I've seen.  It was still short by about 90 yds from the buoy distance over about 1700 yds, but something I'm quite happy with.

    Edit... the FIT file recorded is a little weird, however.  Garmin Connect shows 1682 yds, strava thinks I did 4244 yds and DCR Analyzer is showing a funny distance plot for the 945 file.

    Secondary Edit... Noting DCR Analyzer's battery drain section for my 2 open water swims shows fairly high battery usage in these cases.  Each swim was approx 30 minutes.  One drained 10% and the other 13% estimating total watch capacity from 100% between 5-7 hrs in OWS mode.  I had a phone in my buoy but am not sure if the watch tries to rely on LTE in these cases or not.  In past swims with my 935 live track even seemed to work in this setup so would have hoped 945 LTE would have been in a lower battery usage condition here.

  • Thank you very much!  That is an impressive track for open water.

  • Another good track today, I think within ~30 yds of my buoy GPS device track for distance recorded, but also another weird fit file artifact.

    Reviewing with DCR Analyzer shows distance plot really weird:

    Garmin Connect seems to not use whatever is throwing this offset into the fitfile, but Strava by default seems to we wildly thrown off by it.  In this case Strava is showing my activity at 19184 yds.

    Strava does, however, seem to realize this is odd and offers a "correct distance" option on the web that seems to generally resolve it.

    It's not perfectly in line with what the buoy or Garmin Connect show, but a bit better than before :)

  • I'm having the same issue Re: strava sync and them reporting an odd distance.  I am so far really impressed with the distance the watch is reporting in real time while swimming.  When I use the correct distance, it then seems to do something weird to the time and almost cuts it in half.  I have reached out to both Garmin and Strava to see

  • Curious… did your first OWS distance sync correctly? My files almost looked like there was some weird cumulative swim distance offset being applied in the latter files for the “distance” field in the FIT files.

  • For me it seems the error has been there since my first open water swim.