IRPCS: International Regulations for Preventing Collisions at Sea

(as amended by Resolutions A464(XII), A626(15), A678(16), A736(18) and A.910(22)), (updated 2017)

The International Regulations for Preventing Collisions at Sea (IRPCS), often called COLREGs, are critical for ensuring safety and order on the water. These rules provide a universal framework for understanding vessel hierarchy & signalling intentions and avoiding dangerous situations, making them essential knowledge for anyone operating a vessel. Without a solid understanding of the IRPCS, even experienced mariners risk miscommunication and potential collisions.

That’s where we come in—our resources are designed to simplify these complex rules, making them accessible and easy to learn. Whether you’re a novice sailor or a seasoned skipper, we can help you navigate the IRPCS confidently and clearly.

Use our easy-to-understand, plain English rule book with helpful interpretations of what each rule means.

IRPCS are the global marine equivalent of the Highway Code. The International Maritime Organisation (IMO) published them in October 1972, and they entered into force in July 1977.

The 1972 Convention updated and replaced the Collision Regulations of 1960, which came into force at the same time as the 1960 SOLAS Convention.

They cover how all vessels should behave at sea, including how and where the regulations apply and how vessels should react when meeting each other. Additionally, the code covers what seafarers should do when in sight of each other, not in sight of each other, and in restricted visibility.

IRPCS outlines a hierarchy, defining types of seagoing vessels primarily based on manoeuvrability. It also includes what each vessel type should display in different circumstances, such as day shapes, lights, and sounds.

It considers three primary situations:

  • What we should always do,
  • what to do when in sight of another vessel,
  • and what to do in restricted visibility (fog).

The overarching principle of the IRPCS is that every vessel, regardless of its status, must maintain a proper lookout for other seagoing vessels. Everyone is expected to avoid a collision regardless of the rules, and the rules provide a mechanism for resolving collision situations amicably.

No one has the right-of-way at sea; the regulations offer straightforward definitions to determine which vessel should stand on (remain on its course) and which vessel should give way (alter course) in a collision situation.

Most race organising bodies use the Racing Rules of Sailing (RRS) from World Sailing; however, these predominantly reflect the IRPCS. While racing, participants must adhere to the IRPCS when crossing paths with vessels not racing and any vessel after dusk.

Use the dropdown to filter different sections of the rule book, or click on a rule to find more information, including tools to help you understand its meaning.