# Halcyon Dive Systems vs nDeco

The clearest difference is rating: Halcyon Dive Systems at 5.0 against nDeco's 2.0. Halcyon Dive Systems also leads on update cadence (every 2 weeks vs every 7 months) and ratings volume (8 vs 1). nDeco's advantage is monetization model (free vs ad-supported). On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

Halcyon Dive Systems holds the better App Store score, 5.0 against 2.0. That said, the two scores are not equally well evidenced: Halcyon Dive Systems has 8 ratings behind it against 1, so its average is the more settled of the two.

Halcyon Dive Systems ships an update every 2 weeks, nDeco every 7 months. The most recent releases landed on October 4, 2026 and September 27, 2026 respectively.

## The numbers

| Metric | Halcyon Dive Systems | nDeco |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (8 ratings)](https://appshunter.io/ios/app/halcyon-dive-systems-diving/id6738069654/reviews)** | [2.0 (1 ratings)](https://appshunter.io/ios/app/ndeco/id6741527911/reviews) |
| Number of ratings | **8** | 1 |
| Positive reviews | — | 0.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 2 weeks** | Every 7 months |
| Monetization | Ad-supported | **Free** |
| Size | 159 MB | 73 MB |
| Requires iOS | **16.0** | 17.2 |
| Devices | iPhone | **iPhone, iPad** |
| Age rating | 4+ | 4+ |
| Developer | [Halcyon Dive Systems](https://appshunter.io/developer/1779189368) | [Eyal Vardi](https://appshunter.io/developer/988684101) |

## What reviewers say

### Halcyon Dive Systems

[App page](https://appshunter.io/ios/app/halcyon-dive-systems-diving/id6738069654)

This app helps divers log, track, and share their underwater experiences. It offers integration with dive computers, personalized settings, and a community forum for connecting with other divers.

**Highlights:** Symbios integration for dive computer settings, Detailed dive logging and progress tracking, Social logbook for sharing dive stories, Connect with a global diving community, Personalized dive tips and advice, Exclusive benefits for Halcyon owners

**Features:** macOS Compatibility, Apple Wallet, Vision Pro support

**In-app purchases:** none


### nDeco

[App page](https://appshunter.io/ios/app/ndeco/id6741527911)

Plan multi-segment dives with ease using U.S. Navy and Bühlmann decompression models. Get instant dive information, depth limit guidance, and surface interval recommendations for safe underwater adventures.

**Highlights:** Multi-segment dive planning, U.S. Navy & Bühlmann decompression models, Depth limit guidance, Instant dive information, Surface interval recommendations, Metric/imperial unit flexibility

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Halcyon Dive Systems free?

Halcyon Dive Systems is free to download, with no in-app purchases.

### Is nDeco free?

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

### Which has better reviews, Halcyon Dive Systems or nDeco?

Halcyon Dive Systems is rated higher. Halcyon Dive Systems averages 5.0 out of 5 from 8 ratings, while nDeco averages 2.0 from 1 ratings.

### Do Halcyon Dive Systems or nDeco have ads?

Neither Halcyon Dive Systems nor nDeco shows ads.

### Which is updated more often, Halcyon Dive Systems or nDeco?

Halcyon Dive Systems ships an update every 2 weeks, and nDeco every 7 months. Most recently, Halcyon Dive Systems was updated on October 4, 2026 and nDeco on September 27, 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.*