Learn more about planning and navigating routes on boating adventures in NauticEd’s Coastal Navigation course. Or, just sign up with the FREE (no obligation) Navigation Rules course.

IALA-A and IALA-B Navigation Marks and Atons

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Getting confused about Lateral Navigation Marks and ATONs? There are two systems in the world. IALA-A and IALA-B. Basically, the colors are opposite but here is the infographic.

This information and everything else you need to know about coastal navigation is in the NauticEd Coastal Navigation Course. It’s only $39. Upon completion, the course is added to your globally accepted sailing resume.

Info graphic showing IALA-A and IALA-B systems

Infographic showing IALA-A and IALA-B systems

Here is a world map of where these systems are used.

  • On IALA-B use “red – right – returning”. i.e. put the red buoy on your right when returning.
  • On IALA-A you use the mnemonic “Is there any red port left” to memorize which color buoy you pass on which side of your boat (when returning). i.e. take red buoy to your port (which is the left side of your boat.). Universally, “Is there any red port left?” also works for memorizing what color lights are on your boat. i.e. The red light is mounted on your port side of your boat which is the left side of your boat. For IALA-A is is also easy to remember that you match the color of your boats light to the buoy light. i.e. Red to Red and Green to Green.
IALA Regions

IALA Regions

Just FYI: IALA stands for International Association of Marine Aids to Navigation and Lighthouse Authorities.

You can learn more with the Coastal Navigation Course and Free Navigational Rules

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Learn more about planning and navigating routes on boating adventures in NauticEd’s Coastal Navigation course. Or, just sign up with the FREE (no obligation) Navigation Rules course.

Author

  • Grant Headifen

    Grant Headifen is a USCG-certified Master Mariner (50-Ton), founder of NauticEd, and one of the sailing world's most recognized educators. With 46 years on the water, charters across 40+ global destinations, 5 sailing books, 30+ online courses, and 300,000+ students worldwide, Grant brings real-world expertise to every article. He pioneered fractional boat ownership through SailTime and serves on the Texas Boater Safety Advisory Board. NauticEd is the only U.S. sailing education body recognized by the U.S. Coast Guard under American National Standards.

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Last updated on June 24th, 2025