Subsurface vs OSTConf
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Subsurface
This application allows divers to manage their dive logs on their mobile devices. It supports editing dive data and downloading new information from compatible dive computers. Optional cloud synchronization is available for seamless data transfer with desktop versions.
- Mobile dive log management
- Edit dive data
- Download from Bluetooth LE dive computers
- Optional cloud synchronization
- Open-source and free
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Subsurface-mobile is an iOS dive log application based on Subsurface, the best free open source dive log application available on Windows, Mac and Linux. Subsurface-mobile allows you to access your dive log on your tablet or phone, edit the data and even download new dive information from many Bluetooth LE enabled dive computers. Using a free Subsurface Cloud Storage account you can synchronize your dive data with the Subsurface desktop application (while significantly increasing the usefulness, the cloud account is not required to use Subsurface-mobile). To get support from the developers, please use the in-app menu entry "Ask for support" Please check out the Subsurface-mobile user manual: https://subsurface-divelog.org/documentation/subsurface-mobile-v3-user-manual (also available from within the app) Subsurface-mobile is free and open source. No ads, no commercial anything. And it comes with free cloud storage (if you decide to use that - it's optional). Your data aren't used for anything, nothing gets monetized.
OSTConf
Configure your dive computer settings and parameters wirelessly. Update date, time, custom text, gas mixes, and deco settings. Compatible with recent Bluetooth-enabled dive computers.
- Read and modify settings
- Update date and time
- Set custom text
- Configure gas mixes
- Set deco parameters
- Upgrade firmware
- Retrieve device information
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OSTConf is an application for configuring your OSTC dive computer. It allows you to read and modify settings and parameters of dive computers manufactured by heinrichs weikamp GmbH. Using Bluetooth LE technology, you can retrieve device information, update date and time, custom text, set up your gas mixes and deco parameters as well as upgrading the firmware. OSTConf is compatible with recent Bluetooth-capable OSTC dive computers such as OSTC 2, OSTC plus, OSTC sport, OSTC TR, and OSTC 4. Note that due to the iOS hardware only OSTC devices with BLE are supported. OSTC4: The firmware file contains up to three parts. Please start the firmware update multiple times to ensure that all parts are updated.
Screenshots
Verdict
The clearest difference is review sentiment: Subsurface at 63% against OSTConf's 25%. Subsurface also leads on update cadence (every 2 months vs every 5 months). On price, ads, in-app purchases and monetization model there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
Subsurface ships an update every 2 months, OSTConf every 5 months. Both last shipped on October 6, 2026.
| Parameter | Subsurface | OSTConf |
|---|---|---|
| Price | Free | Free |
| Rating | 4.5 (48 ratings) — better | — |
| Positive reviews | 63.3% of reviews — better | 25.0% of reviews |
| Number of ratings | 48 — better | — |
| Update frequency | Every 2 months — better | Every 5 months |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | Free |
| Devices | iPhone, iPad | iPhone, iPad, iPod — better |
| Requires iOS | 17 | 16.0 — better |
| Further details — not scored | ||
| Size | 52 MB | 3 MB |
| Age rating | 4+ | 4+ |
| Developer | Dirk Hohndel | Kai-Uwe Sattler |
Customer experience
Subsurface
OSTConf
In-app purchases
Subsurface
No in-app purchases
OSTConf
No in-app purchases
