Currently, Swim.com does not support open water swims recorded by GPS devices.
In Spring 2020, we will be adding support for manually entering open water swim information. Eventually, we will likely also be adding support for open water swim files recorded by a watch, but there is currently no development timetable for this.
A few notes on open water swimming:
With open water swim data recorded by a device, it can be hard to judge your improvement and progress based on data alone.
This is because swims performed by the same person in the same body of water on different dates are subject to varying tides, wind, water and air temperature, currents, etc., which could provide a slower time result even if you have actually become more fit and are swimming faster and in turn make it harder to see if you are improving. Also, many times two swims of the exact distance in the same body of water will not record the same distance because each time the watch is submerged it loses contact with the satellite and tries to regain each time it is out of the water. There is about a 10% +/- margin of error.
Additionally, open water swims are hard to compare on leaderboards, because two swims of the same length or course in different bodies of water are not entirely comparable because of differences in tides, wind, water and air temperature, currents, etc. For example, a person swimming in warmer water with a wetsuit and a tide or current pushing them will swim the same course length a lot faster than someone without a wetsuit in slightly colder water who might be battling a headwind.
Some watches that Swim.com supports have both an open water and a lap swim mode. Open water swim files will currently be rejected by the Swim.com servers because they are unable to parse the data. The system is currently only set up to parse lap swim files.
Open water and lap swim tracking modes on watches differ in that GPS records the distance for open water while lap swim distance is collected by utilizing the device's internal accelerometer, a pre-programmed course length, and the motion algorithms programmed within the device's app (whether native or Swim.com).
In order to get an accurate result for lap swimming, the user must program in the correct course length of the pool because the motion pattern generated by a swimmer pushing off the wall with his legs (rapid acceleration after a pause in stroke pattern) during a flip turn or wall push off is what signals to the watch that you have completed a length. In open water swims, that motion pattern is not present and that is why a distance cannot be calculated in this manner and is what makes GPS necessary.