Subsurface vs AWU2UDDF
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.
AWU2UDDF
Export underwater depth and temperature data from your Apple Watch to a standard UDDF XML file. This file can then be imported into popular diving log software for comprehensive record-keeping. It seamlessly integrates with the Health App and HealthKit.
- Export underwater depth and temperature data
- Standard Universal Dive Data Format (UDDF) XML output
- Import into Macdive or Subsurface
- Integrates with Health App and HealthKit
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AWU2UDDF is used to export underwater depth and temperature data collected on your Apple Watch into a standard Universal Dive Data Format (UDDF) XML file. That file can then be imported into standard diving log software such as Macdive or Subsurface to complete your diving log. AWU2UDDF integrates with the Health App and the HealthKit framework to access the depth and temperature date stored by the phone.
Screenshots
Verdict
The clearest difference is review sentiment: AWU2UDDF at 100% against Subsurface's 63%. AWU2UDDF also leads on rating (5.0 vs 4.5). Subsurface's advantage is update cadence (every 2 months vs every 14 months) and ratings volume (48 vs 2). 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.
AWU2UDDF holds the better App Store score, 5.0 against 4.5. That said, the two scores are not equally well evidenced: Subsurface has 48 ratings behind it against 2, so its average is the more settled of the two. Written reviews point the same way: 63% of Subsurface's written reviews are positive against 100% of AWU2UDDF's.
Subsurface ships an update every 2 months, AWU2UDDF every 14 months. The most recent releases landed on September 18, 2026 and September 6, 2026 respectively.
| Parameter | Subsurface | AWU2UDDF |
|---|---|---|
| Price | Free | Free |
| Rating | 4.5 (48 ratings) | 5.0 (2 ratings) — better |
| Positive reviews | 63.3% of reviews | 100.0% of reviews — better |
| Number of ratings | 48 — better | 2 |
| Update frequency | Every 2 months — better | Every 14 months |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | Free |
| Devices | iPhone, iPad — better | iPhone |
| Requires iOS | 17 | 16.0 — better |
| Further details — not scored | ||
| Size | 52 MB | 1 MB |
| Age rating | 4+ | 4+ |
| Developer | Dirk Hohndel | Douglas Junkins |
Customer experience
Subsurface
AWU2UDDF
In-app purchases
Subsurface
No in-app purchases
AWU2UDDF
No in-app purchases
