Subsurface

Subsurface is a free, open‑source dive log application that runs on Windows, macOS and Linux. It lets recreational, technical and free‑divers record dives manually, import them from dive computers, or bring in data from other log programs and websites. The software supports a broad range of dive computers and can combine data from multiple devices into a single profile, displaying depth, tank pressure and consumption curves with visual cues for velocity and gas use.

The program includes a planner that can generate dive profiles using Bühlmann ZH‑16 or VPM‑B models, and it handles single‑ and multi‑tank dives with air, Nitrox or TriMix. Users can tag dives, filter by location, tags or dive partners, group dives into trips, and edit several entries simultaneously. Statistics such as SAC rate, partial pressures and deco calculations are generated automatically.

Subsurface offers optional cloud storage for syncing logs across Android and iOS devices via Subsurface‑mobile, and it can produce printable dive books. The interface is available in roughly twenty languages and is maintained by an active developer community.