# Subsurface vs OSTConf

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.

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.

## The numbers

| Metric | Subsurface | OSTConf |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.5 (48 ratings)](https://appshunter.io/ios/app/subsurface-mobile/id1093217161/reviews)** | — |
| Number of ratings | **48** | — |
| Positive reviews | **63.3% of reviews** | 25.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 2 months** | Every 5 months |
| Monetization | Free | Free |
| Size | 52 MB | 3 MB |
| Requires iOS | 17 | **16.0** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Dirk Hohndel](https://appshunter.io/developer/1093217160) | [Kai-Uwe Sattler](https://appshunter.io/developer/500229044) |

## What reviewers say

### Subsurface

[App page](https://appshunter.io/ios/app/subsurface-mobile/id1093217161)

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.

**Highlights:** Mobile dive log management, Edit dive data, Download from Bluetooth LE dive computers, Optional cloud synchronization, Open-source and free

**In-app purchases:** none


### OSTConf

[App page](https://appshunter.io/ios/app/ostconf/id1404182943)

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.

**Highlights:** Read and modify settings, Update date and time, Set custom text, Configure gas mixes, Set deco parameters, Upgrade firmware, Retrieve device information

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Subsurface free?

Subsurface is free to download, with no in-app purchases.

### Is OSTConf free?

OSTConf is free to download, with no in-app purchases.

### Do Subsurface or OSTConf have ads?

Neither Subsurface nor OSTConf shows ads.

### Which is updated more often, Subsurface or OSTConf?

Subsurface ships an update every 2 months, and OSTConf every 5 months. Most recently, Subsurface was updated on October 6, 2026 and OSTConf on October 6, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*