Garmin has officially launched a new stable firmware update, version 25.20, specifically tailored for the Descent Mk3 and Mk3i dive computers. This latest release focuses on expanding the utility of Garmin’s premier diving wearables, introducing specialized tools for technical divers while refining the overall accuracy of surface data and log reporting.
Enhanced Data Synchronization with Dive Setup Sharing
One of the standout features in this update is the introduction of Dive Setup Sharing. This tool streamlines the preparation process by allowing users to wirelessly transmit critical configurations—such as gas lists and conservatism settings—from one Garmin computer to another. This is particularly useful for divers who use multiple devices or those who want to ensure their backup unit is perfectly synced with their primary computer without manual data entry.
Advanced Support for Sidemount Diving
The Descent Mk3i receives several exclusive upgrades in this cycle aimed at the sidemount community. A new Sidemount support feature provides proactive alerts if a significant pressure discrepancy is detected between two independent tanks. Complementing this is the RTR (Remaining Transmit Time) data field, which has been optimized to display the air-time status of whichever tank has the lower remaining pressure, ensuring divers have immediate visibility into their most critical gas supply.
Connectivity and Interface Refinements
Beyond new features, version 25.20 addresses technical stability and interface logic. Users of the Descent S1 buoy will notice improved connection consistency with the Mk3i, reducing the likelihood of signal drops during a session. Additionally, the GF99 data field—which tracks the current gradient factor relative to the M-value—has been adjusted for better behavior while at the surface, providing a more seamless transition between dive and post-dive modes.
Bug Fixes and Installation Instructions
This update also resolves a specific logging error where the ending tank pressures in the dive history could occasionally display incorrect values on the Mk3i. By cleaning up these data discrepancies, Garmin ensures that post-dive analysis remains as accurate as possible.
To install the 25.20 update immediately, you can trigger the download manually on your wearable. Navigate to the Menu, select System, then Software Update, and tap Check For Updates to begin the process.
Change Log Summary:
- Adds Dive Setup Sharing – the ability to copy your gas list, conservatism, and more to another Garmin computer.
- [Mk3i Only] Adds Sidemount support – Get a notification when the pressure difference between two of your tanks differs.
- [Mk3i Only] Adds RTR datafield – Show the air time remaining in the lower of two sidemount tanks.
- [Mk3i Only] Improves connection stability with the Descent S1 buoy.
- Improves the behavior of the GF99 data field on the surface.
- [Mk3i Only] Fixed ending tank pressures in the dive log, potentially showing an incorrect value.
Also Read:Â Is the Garmin Fenix 9 Worth the Wait? My Deep Dive into the 2026 Rumors
