Subsurface: A Dive Log Tracking App

Subsurface is free software that helps scuba divers record, organize, and analyze their dive data. If you dive regularly, you need a place to log where you went, how deep you went, water temperature, equipment used, and other details. Subsurface is that logbook—it works on your computer or phone and makes it easy to store all your diving history in one place.

The software imports data directly from your dive computer (the device you wear underwater that tracks depth, time, and other metrics). Instead of manually typing in dive details, you just plug in your dive computer and click "Import"—Subsurface reads the data automatically. It supports hundreds of different dive computer models. Once your dives are logged, the app visualizes the information with graphs and maps, showing you things like depth over time or where in the world you've dived. You can also add notes, track which gear you used, and review your diving history.

Divers of all levels use this: recreational divers who want to keep memories of their trips, technical divers who need detailed analysis of their dive profiles, and dive instructors who track their students' progress. Because it's free and open-source, it's especially popular among the diving community as an alternative to expensive proprietary software.

The project was started by Linus Torvalds (the creator of Linux) in 2011 out of frustration with poor diving software options, and it's been actively developed ever since. It runs on Windows, Mac, Linux, iOS, and Android, so whether you're at home reviewing past dives or on a boat trip logging a new one, you have access to your data. The README notes that this particular repository is a legacy fork—the active development happens elsewhere, so if you're looking to contribute or download the latest version, check the official Subsurface project instead.