How to rejoin the two parts
- Find both parts. The ride or run before the slip is one activity, and the one you started afterwards is another. Both show up in your activity list once they have synced.
- Get a file for each part. Where the files come from depends on where you keep your activities. The export guide has a section for each watch, bike computer and app.
- Drop both files above. The order doesn't matter, because FitMerge sorts the parts by time.
- Look at the result, then save. The totals appear above the map, with a dashed grey line across the break. Choose a format and download; FIT is already selected.
FitMerge reads the two files where they are, on your device, and sends neither to a server.
What you pressed, and why it made two activities
A pause keeps one activity open. Saving or finishing closes it. Anything you record after that is a new activity, even if you start it a minute later at the same spot.
On a Forerunner 255, Garmin's manual says pressing STOP opens a list that includes Resume, Save, Resume Later and Discard. Other models differ, so read the manual for yours. In the Strava app, the pause button pauses, and Strava's help says Finish takes you to a screen where you tap Save Activity or Discard Activity. This is how both looked in November 2026.
A discarded part is gone. Strava says it can't recover an activity you discarded and confirmed, and Garmin's manual has a Discard option for the same purpose. Only parts you saved can be joined.
How long a break can be
Between the two parts you stood at a crossing, bought a coffee or looked for the right button. The merged activity treats that time as a pause, so it is not moving time and your average speed doesn't drop for it. Distance and moving time cover only what was recorded.
A short break needs nothing from you. If it was longer than 2 hours, the page shows a box that says These are parts of the same activity. Merge anyway. Tick it to download. If it was longer than 12 hours, the page doesn't merge the files at all.
If you rode on for a while before you started again, the second part begins away from where the first stopped. The dashed line on the map joins the two ends, and the distance in between is not in the totals. Past 1 km the page adds a warning; you can still download.
Laps and the climb in between
The laps you pressed in the first part and the second part both appear in the merged FIT, and a part you never lapped shows up as a single lap. We checked this with two GPX parts saved as FIT: Strava showed two laps.
You probably stayed put during the break, so the option Count elevation change across gaps can stay off, as it is by default. If you did go up or down, the battery guide explains what the option adds.
The other mistake: you forgot to stop
Maybe the recording ran on after you got home and now the end of your activity is a sofa. That is one activity with extra minutes, and joining files can't remove them. You need a trim.
- Strava: its Crop tool can cut the minutes at the end off the activity you already have.
- Garmin Connect: Trim Activity changes the start or end time, on the website and in the app. Garmin's help says an activity that came from a GPX or TCX file can't be trimmed, and a trim isn't passed on to Strava. Garmin's answer has the steps.
Replacing the two parts
Delete the two parts and upload the merged file to wherever you keep your activities. The steps are in the Strava guide and the Garmin Connect guide.
Questions
I pressed Save instead of Pause. Is the first part safe?
If you saved it, it is an ordinary finished activity, and you will find it in your activity list. Watches that offer Resume Later describe it in the manual as suspending the activity so you can carry on later. Read the manual for your model before relying on it.
My watch lists both parts. Do I have to change anything on it?
No. FitMerge reads copies of the files and leaves the originals alone, so both parts stay where they are until you delete them yourself.
I paused properly earlier on. Is that pause still there?
Yes. A FIT part keeps the timer stops and starts your device wrote, so that pause is still in the merged file, and the break after the slip is added as one more. A GPX part has no pause records; the GPX guide says how its moving time is worked out.
My watch stopped and I carried on with my phone. Is this the page for that?
Close, but the battery guide is written for two devices.