COLREG Rules — International Regulations for Preventing Collisions at Sea
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A
Part A — General
3- 1 Application COLREG applies to all vessels on the high seas and in connected waters navigable by seagoing vessels, subject to closely conforming local special rules and IMO-adopted traffic separation schemes.
- 2 Responsibility Nothing in these Rules shall exonerate any vessel from the consequences of neglecting these Rules or neglecting any precaution required by ordinary practice of seamanship.
- 3 General Definitions Defines key terms used throughout the COLREGs including vessel, power-driven vessel, sailing vessel, restricted visibility, and more.
B
Part B — Steering & Sailing Rules
16Section I.Conduct in any condition of visibility
- 4 Application Rules in Section I apply in any condition of visibility.
- 5 Look-out Keep watch at all times with your eyes and ears, and use radar, AIS and every other means on board to judge the situation and the risk of collision.
- 6 Safe Speed Always go slowly enough that you can still avoid a collision and stop in time, judged against visibility, traffic, manoeuvrability and conditions.
- 7 Risk of Collision Every vessel shall use all available means to determine if risk of collision exists. If in doubt, such risk shall be deemed to exist.
- 8 Action to Avoid Collision When you act to avoid a collision, act early and make the change large enough for the other vessel to see, then check that it is working.
- 9 Narrow Channels In a narrow channel, stay on the starboard side as far as it is safe, and don't block vessels that can only navigate inside it.
- 10 Traffic Separation Schemes In a traffic separation scheme, follow your lane in the direction of the traffic, cross it at right angles if you must, and keep clear of the separation zone.
Section II.Conduct in sight of one another
- 11 Application Rules 11 to 18 cover vessels that can see each other with their own eyes, not only on radar.
- 12 Sailing Vessels When two sailing vessels approach, the one with wind on port side keeps clear. When both have wind on same side, the windward vessel keeps clear.
- 13 Overtaking If you are overtaking, it is your job to keep clear of the vessel ahead until you are past and well clear, whatever type of vessel you are.
- 14 Head-on Situation When two power-driven vessels in sight meet on reciprocal or nearly reciprocal courses with risk of collision, each shall alter to starboard to pass port to port.
- 15 Crossing Situation When two power-driven vessels are crossing, the vessel which has the other on her starboard side shall keep out of the way.
- 16 Action by Give-way Vessel As the give-way vessel, make your move early and make it big, so you pass at a safe distance and the other vessel can see what you are doing.
- 17 Action by Stand-on Vessel The stand-on vessel shall keep her course and speed, but may take action when it becomes apparent the give-way vessel is not acting.
- 18 Responsibilities Between Vessels Rule 18 sets the basic responsibilities between vessel types. Constrained-by-draught vessels receive special consideration but are not simply another rung in a fixed hierarchy.
C
Part C — Lights & Shapes
12- 20 Application (Lights) Show your navigation lights between sunset and sunrise and whenever visibility is poor, and day shapes during the day.
- 21 Definitions (Lights) Defines masthead light, sidelights, sternlight, towing light, all-round light and flashing light.
- 22 Visibility of Lights Specifies minimum visibility ranges for lights based on vessel length.
- 23 Power-driven Vessels Underway Power-driven vessels underway shall exhibit masthead light(s), sidelights, and sternlight. Vessels 50m+ require two masthead lights.
- 24 Towing and Pushing Vessels towing or pushing display additional masthead lights and a yellow towing light. Three masthead lights if tow exceeds 200m.
- 25 Sailing Vessels Underway and Vessels Under Oars Sailing vessels show sidelights and sternlight. May optionally show red over green all-round lights at the masthead.
- 26 Fishing Vessels Fishing vessels show green over white when trawling, red over white for other fishing, and sidelights plus sternlight when making way.
- 27 Vessels Not Under Command or Restricted in Ability to Manoeuvre NUC shows two red all-round lights vertically. RAM shows red-white-red all-round lights vertically.
- 28 Vessels Constrained by Their Draught A vessel limited by her draught can add three red all-round lights, one above the other, or a black cylinder by day.
- 29 Pilot Vessels A pilot vessel on duty shows white over red all-round lights at the masthead. When underway, also sidelights and sternlight.
- 30 Anchored Vessels and Vessels Aground Anchored vessels show an all-round white light forward and another aft (lower). Vessels aground additionally show two red all-round lights.
- 31 Seaplanes Where it is impracticable for a seaplane to exhibit lights of the exact characteristics, it shall exhibit lights as closely similar as possible.
D
Part D — Sound & Light Signals
6- 32 Definitions (Sound Signals) Whistle = any Annex III-compliant sound appliance. Short blast ≈ 1 s. Prolonged blast = 4-6 s. Get the duration wrong and the meaning changes.
- 33 Equipment for Sound Signals Whistle from 12 m, bell added from 20 m, gong added from 100 m — and the gong's tone must not be confused with the bell's.
- 34 Manoeuvring and Warning Signals One short blast means starboard, two means port, three means astern propulsion, and five or more rapid blasts mean doubt or danger.
- 35 Sound Signals in Restricted Visibility In restricted visibility, power-driven vessels making way sound one prolonged blast every 2 minutes. Vessels not making way sound two prolonged blasts.
- 36 Signals to Attract Attention To get another vessel's attention you can use a light or sound signal, as long as it can't be confused with any signal the rules define.
- 37 Distress Signals When in distress and requiring assistance, vessels shall use the signals described in Annex IV (red flares, SOS, MAYDAY, DSC, EPIRB and others).
E
Part E — Exemptions
1F
Part F — Verification of Compliance
3- 39 Definitions (Verification of Compliance) Defines the terms used by Part F: audit, Audit Scheme, Code for Implementation and audit standard — the vocabulary of the IMO Member State Audit Scheme.
- 40 Application (Verification of Compliance) Contracting Parties shall use the Code for Implementation when carrying out their obligations and responsibilities under the Convention.
- 41 Verification of Compliance Every Contracting Party is subject to periodic IMO audits verifying its compliance with and implementation of the Convention.
Selected COLREG topics
- 13Rule 13: OvertakingFor vessels in sight, every overtaking vessel keeps clear until finally past and clear. Rule 13 takes precedence over Part B Sections I and II; it does not override the other Parts of COLREG.
- 14Rule 14: Head-on situationWhen two power-driven vessels are meeting on reciprocal or nearly reciprocal courses so as to involve risk of collision each shall alter her course to starboard so that each shall pass on the port side of the other.
- 15Rule 15: Crossing situationWhen two power-driven vessels are crossing so as to involve risk of collision, the vessel which has the other on her own starboard side shall keep out of the way and shall, if the circumstances of the case admit, avoid crossing ahead of the other vessel.
- 18Rule 18: Responsibilities between vesselsRule 18 does not rank not-under-command above restricted-in-ability-to-manoeuvre vessels. Its duties are subject to Rules 9, 10 and 13; they do not create an absolute right of way.
- 19Rule 19: Conduct in restricted visibility(a) This Rule applies to vessels not in sight of one another when navigating in or near an area of restricted visibility.
- Lights & shapes (Rules 20–31)Visual examples of navigation lights and day shapes.
Practise
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More resources
COLREG, in one paragraph
COLREG is the Convention on the International Regulations for Preventing Collisions at Sea, 1972. It was adopted on 20 October 1972 and entered into force on 15 July 1977. As amended, it contains 41 rules in six Parts, A–F, and four Annexes. Rule 1 defines its scope: all vessels on the high seas and in connected waters navigable by seagoing vessels.
What are the COLREGs?
The COLREGs are the 41 rules of the 1972 IMO Convention on the International Regulations for Preventing Collisions at Sea, which apply to all vessels on the high seas and in connected waters navigable by seagoing vessels.
A — General (1–3): Application, responsibility, definitions; B — Steering & Sailing (4–19): Conduct in any visibility, in sight of one another, and in restricted visibility; C — Lights & Shapes (20–31): Navigation lights and day shapes by vessel type;
D — Sound & Light Signals (32–37): Whistle, bell, gong and distress signals; E — Exemptions (38): Specified technical exemptions for eligible older vessels; F — Verification of compliance (39–41): Contracting Parties and the IMO audit scheme.
COLREG structure at a glance
| Part | Rules | What it covers |
|---|---|---|
| A — General | 1–3 | Application, responsibility, definitions |
| B — Steering & Sailing | 4–19 | Conduct in any visibility, in sight of one another, and in restricted visibility |
| C — Lights & Shapes | 20–31 | Navigation lights and day shapes by vessel type |
| D — Sound & Light Signals | 32–37 | Whistle, bell, gong and distress signals |
| E — Exemptions | 38 | Specified technical exemptions for eligible older vessels |
| F — Verification of compliance | 39–41 | Contracting Parties and the IMO audit scheme |
Frequently asked questions
What does COLREG stand for?
COLREG is short for the Convention on the International Regulations for Preventing Collisions at Sea, 1972 — its official full name. It was adopted on 20 October 1972 and has been in force since 15 July 1977. You'll also see COLREGS (the rules themselves), IRPCS (the British abbreviation), RIPA (Spain), RIPAM (France) and KVR (Germany) — all refer to the same IMO text.
Are the COLREGs the same in every country?
(b) Nothing in these Rules shall interfere with the operation of special rules made by an appropriate authority for roadsteads, harbors, rivers, lakes or inland waterways connected with the high seas and navigable by seagoing vessels. Such special rules shall conform as closely as possible to these Rules.
When does Rule 19 apply instead of Rules 11–18?
Rules 4–10 apply in any visibility. Rules 11–18 apply to vessels in sight of one another; Rule 19 applies to vessels not in sight when navigating in or near an area of restricted visibility.
Do COLREGs apply to small boats and jet skis?
(a) These Rules shall apply to all vessels upon the high seas and in all waters connected therewith navigable by seagoing vessels. Small craft are included. Requirements depend on vessel type, length and operating condition; some light and sound provisions have specific small-vessel alternatives or exemptions.
When were the COLREGs last updated?
Checked against the IMO 2026 edition: the latest amendments are Resolution A.1085(28), adopted on 4 December 2013 and effective from 1 January 2016. They added Part F, Rules 39–41, on verification of compliance and the IMO audit scheme.
How many rules are there in the COLREGs?
There are 41 rules in six Parts, A–F. Four Annexes cover the positioning and technical details of lights and shapes; additional signals for fishing vessels fishing in close proximity; sound-signal appliances; and distress signals.
What are the Parts of the COLREGs?
A — General (1–3): Application, responsibility, definitions; B — Steering & Sailing (4–19): Conduct in any visibility, in sight of one another, and in restricted visibility; C — Lights & Shapes (20–31): Navigation lights and day shapes by vessel type; D — Sound & Light Signals (32–37): Whistle, bell, gong and distress signals; E — Exemptions (38): Specified technical exemptions for eligible older vessels; F — Verification of compliance (39–41): Contracting Parties and the IMO audit scheme.
What is the difference between COLREG, COLREGS and IRPCS?
There is no difference in substance: they are three names for one document. COLREG abbreviates the convention's title, COLREGS is the plural people use for the rules themselves, and IRPCS — International Regulations for Preventing Collisions at Sea — is the abbreviation used in British training and exams. RIPA in Spain, RIPAM in France and KVR in Germany are the same convention again under its local name, so Rule 15 means the same thing in every one of them.
What is COLREG 72?
“COLREG 72”, also written COLREG 1972 or COLREGs 72, is the convention with its year attached — the Convention on the International Regulations for Preventing Collisions at Sea, 1972, adopted on 20 October 1972 and in force since 15 July 1977. The 72 distinguishes it from the 1960 collision regulations it replaced. It is not a separate ruleset: it is the same 41 rules in Parts A–F that apply today, as amended.
Is there a PDF of COLREG rules 1–41?
Yes. Use “Download all 41 rules as PDF” at the top of this page: a free A4 file with every rule from 1 to 41, grouped by Part, each with its title, a short study summary and a link to its full page. It is a study summary, not the official text of the Convention.