COLREGs Meaning: Collision Rules for Sailors
Plain-language guide to COLREGs, the international collision-prevention rules covering right of way, lookouts, lights, sound signals, and safe navigation.
Effective from
1977-07-15
Responsible authority
IMO / national maritime authority
What changed
Expanded the glossary entry with practical skipper guidance, clearer breadcrumbs, FAQs, and related safety links.
Editorial note
Reviewed for practical skipper use
This guide explains the term in plain language and connects it to safe navigation, voyage planning, watchkeeping, and related Marstick tools.
Practical planning guidance
COLREGs stands for the Convention on the International Regulations for Preventing Collisions at Sea. These rules help vessels decide how to act when there is risk of collision.
For sailors, COLREGs are most relevant when judging stand-on and give-way responsibilities, crossing situations, overtaking, head-on approaches, narrow channels, traffic separation schemes, and restricted visibility.
A proper lookout is central to COLREGs. Crews should use sight, hearing, AIS, radar where fitted, and regular bearing checks instead of relying on one screen or one app.
Navigation lights, day shapes, and sound signals communicate vessel type, activity, and intention. They matter at night, in poor visibility, and around commercial traffic.
COLREGs do not remove the skipper’s duty to avoid collision. Even a stand-on vessel may need to act if the other vessel does not take early and effective avoiding action.
Use COLREGs together with local regulations, weather checks, route planning, crew briefings, and conservative speed decisions in crowded or low-visibility waters.
Frequently asked questions
What does COLREGs mean?
COLREGs means the Convention on the International Regulations for Preventing Collisions at Sea.
Do small boats need to follow COLREGs?
Yes. Recreational sailing boats, motorboats, commercial vessels, and other craft must follow the collision-prevention rules where they apply.
Are COLREGs the same as right-of-way rules?
Right-of-way is only part of COLREGs. The rules also cover lookouts, safe speed, collision risk, lights, shapes, sound signals, narrow channels, and restricted visibility.
Can AIS replace COLREGs?
No. AIS improves awareness, but COLREG decisions still require watchkeeping, visual checks, radar or sound signals where appropriate, and early avoiding action.