Skip to content

Garmin FIT Format

FIT (Flexible and Interoperable Data Transfer) is the file format Garmin uses to record every activity on its watches, including dives. It is a compact binary format, so unlike UDDF you can't read it in a text editor. Files use the .fit extension.

File extension

Files in this format use the .fit extension — for example, 2024-05-12-09-30-00.fit. When you download a dive from Garmin Connect the .fit file arrives inside a .zip file. DiveHub accepts either one.

What is inside a FIT dive file?

A FIT dive file records the dive as a series of messages. For a dive this includes:

  • The depth profile, with a sample every second or so
  • Water temperature
  • The gases you dived with, such as air, nitrox and trimix
  • Dive settings such as the decompression model and gradient factors
  • A summary with maximum depth, average depth and bottom time
  • The watch name, serial number and software version

FIT files also hold activity data a dive log doesn't need, such as heart rate and battery level. DiveHub ignores it.

Which devices create FIT files?

FIT is Garmin's own format, so it comes from Garmin watches. DiveHub supports dives from the Garmin Descent Mk1, Mk2, Mk2i, Mk2S, Mk3 and G1. See Exporting Dives from Garmin Descent for how to download the file from Garmin Connect.

Importing FIT files into DiveHub

DiveHub can read FIT files directly, so you don't need to convert them to UDDF first. See Garmin Export for the steps and Importing Dives for the general process.