# IALA Navigation Marks vs IMO Signs

The clearest difference is review sentiment: IMO Signs at 100% against IALA Navigation Marks's 50%. IALA Navigation Marks's advantage is update cadence (every 23 months vs every 95 months) and price ($1.99 vs $3.99). On ads, in-app purchases and monetization model there is nothing between them.

IALA Navigation Marks costs $1.99 and IMO Signs $3.99 up front. Neither carries in-app purchases, so what you see is what you pay.

IALA Navigation Marks ships an update every 23 months, IMO Signs every 95 months. The most recent releases landed on September 10, 2026 and September 21, 2026 respectively.

## The numbers

| Metric | IALA Navigation Marks | IMO Signs |
| --- | --- | --- |
| Price | **$1.99** | $3.99 |
| Positive reviews | 50.0% of reviews | **100.0% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 23 months** | Every 95 months |
| Monetization | Paid | Paid |
| Size | 28 MB | 194 MB |
| Requires iOS | **15.6** | 17.6 |
| Devices | **iPhone, iPad, iPod, Mac** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Smirnov Yury](https://appshunter.io/developer/420438416) | [Sergejs Zeigurs](https://appshunter.io/developer/1439812373) |

## What reviewers say

### IALA Navigation Marks

[App page](https://appshunter.io/ios/app/iala-navigation-marks/id1224059816)

A quick reference guide for sailors and students to identify maritime navigation marks according to the IALA system. It covers buoy shapes, colors, topmarks, and light rhythms for various mark types, aiding in exam preparation and on-water identification.

**Highlights:** Identify lateral, cardinal, and special marks, Covers buoy shape, color, topmark, and light rhythm, Includes day and night views, Practical study aid for seamanship training, Quick lookup on iPhone and iPad

**In-app purchases:** none


### IMO Signs

[App page](https://appshunter.io/ios/app/imo-signs/id1439813671)

This educational app allows users to search for symbols by ID or name. It's designed for studying and reinforcing knowledge in a specific subject area. Enjoy a straightforward learning experience.

**Highlights:** Search by ID, Search by Name, Knowledge rechecking, Study aid

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

**In-app purchases:** none


## Frequently asked questions

### Is IALA Navigation Marks free?

IALA Navigation Marks costs $1.99, with no in-app purchases.

### Is IMO Signs free?

IMO Signs costs $3.99, with no in-app purchases.

### Do IALA Navigation Marks or IMO Signs have ads?

Neither IALA Navigation Marks nor IMO Signs shows ads.

### Which is updated more often, IALA Navigation Marks or IMO Signs?

IALA Navigation Marks ships an update every 23 months, and IMO Signs every 95 months. Most recently, IALA Navigation Marks was updated on September 10, 2026 and IMO Signs on September 21, 2026.

---

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