Paragraph (a): Application
This Rule applies to traffic separation schemes adopted by the Organization and does not relieve any vessel of her obligation under any other Rule.
COLREGs trainerPart B: Steering and Sailing Rules
Rule 10
Traffic Separation Schemes
Proceed in the appropriate traffic lane; cross at right angles where required.
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 Rule 10 on one page
Paragraph (a): Application
This Rule applies to traffic separation schemes adopted by the Organization and does not relieve any vessel of her obligation under any other Rule.
Paragraph (b): Using a scheme
A vessel using a traffic separation scheme shall: (i) proceed in the appropriate traffic lane in the general direction of traffic flow for that lane; (ii) so far as practicable keep clear of a traffic separation line or zone; (iii) normally join or leave a lane at its termination, but when joining or leaving from the side do so at as small an angle to the general direction of flow as practicable.
Paragraph (c): Crossing lanes
A vessel shall, so far as practicable, avoid crossing traffic lanes but if obliged to do so shall cross on a heading as nearly as practicable at right angles to the general direction of traffic flow.
Paragraph (d): Inshore traffic zones
(i) A vessel shall not use an inshore traffic zone when she can safely use the appropriate traffic lane within the adjacent traffic separation scheme. However, vessels of less than 20 m in length, sailing vessels and vessels engaged in fishing may use the inshore traffic zone. (ii) Notwithstanding sub-paragraph (d)(i), a vessel may use an inshore traffic zone when en route to or from a port, offshore installation or structure, pilot station or any other place situated within the inshore traffic zone, or to avoid immediate danger.
Paragraph (e): Separation zones
A vessel other than a crossing vessel or a vessel joining or leaving a lane shall not normally enter a separation zone or cross a separation line except: (i) in cases of emergency, to avoid immediate danger; (ii) to engage in fishing within a separation zone.
Paragraph (f): Near terminations
A vessel navigating in areas near the terminations of traffic separation schemes shall do so with particular caution.
Paragraph (g): Anchoring
A vessel shall so far as practicable avoid anchoring in a traffic separation scheme or in areas near its terminations.
Paragraph (h): Not using the scheme
A vessel not using a traffic separation scheme shall avoid it by as wide a margin as is practicable.
Paragraph (i): Fishing vessels
A vessel engaged in fishing shall not impede the passage of any vessel following a traffic lane.
Paragraph (j): Small craft and sailing vessels
A vessel of less than 20 m in length or a sailing vessel shall not impede the safe passage of a power-driven vessel following a traffic lane.
Paragraphs (k) and (l): Vessels at work in a scheme
(k) A vessel restricted in her ability to manoeuvre when engaged in an operation for the maintenance of safety of navigation in a traffic separation scheme is exempted from complying with this Rule to the extent necessary to carry out the operation. (l) A vessel restricted in her ability to manoeuvre when engaged in an operation for the laying, servicing or picking up of a submarine cable, within a traffic separation scheme, is exempted from complying with this Rule to the extent necessary to carry out the operation. In plain words: a vessel servicing the scheme’s buoys or working on a cable, and showing the RAM signals, need not follow the lane rules where her work requires it. Expect her, and give her room.
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.