Rule 1(a): Where the Rules apply
These Rules shall apply to all vessels upon the high seas and in all waters connected therewith navigable by seagoing vessels.
COLREGs trainerPart A: General
Rules 1–3
General: Application, Responsibility & Definitions
Where the rules apply, who is responsible for compliance, and the key terms used throughout.
Wording follows the International Regulations as printed in the US Coast Guard Navigation Rules handbook (2024), with British spelling, and is shortened in places. Download the rules
Read the whole of Rules 1–3 on one page
Rule 1(a): Where the Rules apply
These Rules shall apply to all vessels upon the high seas and in all waters connected therewith navigable by seagoing vessels.
Rule 1(b) to (e): Local and special rules
(b) Nothing in these Rules shall interfere with the operation of special rules made by an appropriate authority for roadsteads, harbours, 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. (c) Governments may make special rules for additional station or signal lights, shapes or whistle signals for ships of war and vessels in convoy, and additional station or signal lights or shapes for fishing vessels fishing as a fleet. They shall, so far as possible, be such that they cannot be mistaken for any signal in these Rules. (d) Traffic separation schemes may be adopted by the Organization (the IMO) for the purpose of these Rules. (e) A vessel of special construction or purpose that cannot comply fully with the Rules on lights, shapes and sound-signalling appliances shall comply as closely as her Government determines is possible. In plain words: your country, state or harbour can make its own rules for its waters, such as the US Inland Rules or a port’s by-laws. Check the rules for the waters you are in.
Rule 2: Responsibility
(a) Nothing in these Rules shall exonerate any vessel, or the owner, master or crew thereof, from the consequences of any neglect to comply with these Rules or of the neglect of any precaution which may be required by the ordinary practice of seamen, or by the special circumstances of the case. (b) In construing and complying with these Rules due regard shall be had to all dangers of navigation and collision and to any special circumstances, including the limitations of the vessels involved, which may make a departure from these Rules necessary to avoid immediate danger.
Rule 3(a) to (e): Vessels
For the purpose of these Rules, except where the context otherwise requires: (a) "vessel" includes every description of water craft, including non-displacement craft, WIG craft and seaplanes, used or capable of being used as a means of transportation on water; (b) "power-driven vessel" means any vessel propelled by machinery; (c) "sailing vessel" means any vessel under sail provided that propelling machinery, if fitted, is not being used; (d) "vessel engaged in fishing" means any vessel fishing with nets, lines, trawls or other fishing apparatus which restrict manoeuvrability, but does not include a vessel fishing with trolling lines or other fishing apparatus which do not restrict manoeuvrability; (e) "seaplane" includes any aircraft designed to manoeuvre on the water.
Rule 3(f) and (g): NUC and RAM
(f) "vessel not under command" means a vessel which through some exceptional circumstance is unable to manoeuvre as required by these Rules and is therefore unable to keep out of the way of another vessel; (g) "vessel restricted in her ability to manoeuvre" means a vessel which from the nature of her work is restricted in her ability to manoeuvre as required by these Rules and is therefore unable to keep out of the way of another vessel. It includes but is not limited to: (i) a vessel laying, servicing or picking up a navigation mark, submarine cable or pipeline; (ii) a vessel dredging, surveying or in underwater operations; (iii) a vessel replenishing or transferring persons, provisions or cargo while underway; (iv) a vessel launching or recovering aircraft; (v) a vessel engaged in mine clearance operations; (vi) a vessel in a towing operation such as severely restricts the towing vessel and her tow in their ability to deviate from their course.
Rule 3(h) to (m): Draught, underway, sight and visibility
(h) "vessel constrained by her draught" means a power-driven vessel which, because of her draught in relation to the available depth and width of navigable water, is severely restricted in her ability to deviate from the course she is following; (i) "underway" means that a vessel is not at anchor, or made fast to the shore, or aground; (j) "length" and "breadth" mean her length overall and greatest breadth; (k) vessels shall be deemed to be in sight of one another only when one can be observed visually from the other; (l) "restricted visibility" means any condition in which visibility is restricted by fog, mist, falling snow, heavy rainstorms, sandstorms or any other similar causes; (m) "Wing-In-Ground (WIG) craft" means a multimodal craft which, in its main operational mode, flies in close proximity to the surface by utilizing surface-effect action.
A training aid, not the official text. The COLREGs are an IMO convention, and your national authority publishes the version that applies in its waters. Check the rules themselves before you rely on them at sea. Download the rules.