COLREGs Rule 25: Lights and shapes for sailing vessels and oared vessels

Last reviewed: October 14, 2026

Rule 25 covers sailing vessels underway and vessels under oars. A sailing vessel underway must exhibit sidelights and a sternlight. Smaller vessels have options for combined lanterns or a white light, and a vessel under sail and machinery must show a cone.

Applies toSailing vessels underway, vessels under oars, and vessels proceeding under sail when also being propelled by machinery.

What it says

  1. A sailing vessel underway must exhibit sidelights and a sternlight.

    COLREGs Rule 25(a)“A sailing vessel underway shall exhibit:”

  2. A sailing vessel of less than 20 meters in length may combine the sidelights and sternlight in one lantern carried at or near the top of the mast where it can best be seen.

    COLREGs Rule 25(b)“In a sailing vessel of less than 20 meters in length the lights prescribed in paragraph (a) of this Rule may be combined in one lantern”

  3. A sailing vessel underway may also show two all-round lights in a vertical line at or near the top of the mast, red above green. She must not show them together with the combined lantern.

    COLREGs Rule 25(c)“but these lights shall not be exhibited in conjunction with the combined lantern permitted by paragraph (b) of this Rule.”

  4. International: A sailing vessel of less than 7 meters in length must, if practicable, show the paragraph (a) or (b) lights. If she does not, she must have ready at hand an electric torch or lighted lantern showing a white light, to be exhibited in sufficient time to prevent collision.

    COLREGs Rule 25(d)(i)“she shall have ready at hand an electric torch or lighted lantern showing a white light which shall be exhibited in sufficient time to prevent collision.”

  5. Inland: A sailing vessel of less than 7 meters in length that does not show the paragraph (a) or (b) lights must exhibit an all-round white light or have ready at hand an electric torch or lighted lantern showing a white light.

    COLREGs Rule 25(d)(i)“she shall exhibit an all-round white light or have ready at hand an electric torch or lighted lantern showing a white light”

  6. A vessel under oars may exhibit the lights prescribed for sailing vessels.

    COLREGs Rule 25(d)(ii)“A vessel under oars may exhibit the lights prescribed in this Rule for sailing vessels”

  7. A vessel proceeding under sail when also being propelled by machinery must exhibit forward, where it can best be seen, a conical shape with the apex downwards.

    COLREGs Rule 25(e)“A vessel proceeding under sail when also being propelled by machinery shall exhibit forward where it can best be seen a conical shape, apex downwards.”

  8. Inland: A vessel of less than 12 meters in length is not required to exhibit the cone, but may do so.

    COLREGs Rule 25(e)“A vessel of less than 12 meters in length is not required to exhibit this shape, but may do so.”

Common questions

What lights must a sailing vessel underway show?

A sailing vessel underway must exhibit sidelights and a sternlight. If under 20 meters in length, she may combine them in one lantern at or near the top of the mast.

“A sailing vessel underway shall exhibit:”

Does a sailing vessel under 12 meters need a cone when motorsailing?

International: yes, the text requires the cone for a vessel under sail and machinery. Inland: a vessel of less than 12 meters in length is not required to show it, but may.

“A vessel of less than 12 meters in length is not required to exhibit this shape, but may do so.”

What must a vessel under oars show?

A vessel under oars may exhibit the sailing vessel lights. If she does not, she must have ready at hand an electric torch or lighted lantern showing a white light, and Inland she may instead exhibit an all-round white light.

“A vessel under oars may exhibit the lights prescribed in this Rule for sailing vessels”

The text of COLREGs Rule 25

U.S. Coast Guard, Navigation Rules and Regulations Handbook

Rule 25: Sailing Vessels Underway and Vessels Under Oars

International (COLREGs)

(a) A sailing vessel underway shall exhibit:

(i) sidelights;

(ii) a sternlight.

(b) In a sailing vessel of less than 20 meters in length the lights prescribed in paragraph (a) of this Rule may be combined in one lantern carried at or near the top of the mast where it can best be seen. Sailing vessel underway. Same for Inland.

(c) A sailing vessel underway may, in addition to the lights prescribed in paragraph (a) of this Rule, exhibit at or near the top of the mast, where they can best be seen, two all-round lights in a vertical line, the upper being red and the lower green, but these lights shall not be exhibited in conjunction with the combined lantern permitted by paragraph (b) of this Rule. Sailing vessel underway. Same for Inland.

(d) (i) A sailing vessel of less than 7 meters in length shall, if practicable, exhibit the lights prescribed in paragraph (a) or (b) of this Rule, but if she does not, she shall have ready at hand an electric torch or lighted lantern showing a white light which shall be exhibited in sufficient time to prevent collision.

(ii) A vessel under oars may exhibit the lights prescribed in this Rule for sailing vessels, but if she does not, she shall have ready at hand an electric torch or lighted lantern showing a white light which shall be exhibited in sufficient time to prevent collision. Sailing vessel underway—less than 7 meters in length. Same for Inland.

(e) A vessel proceeding under sail when also being propelled by machinery shall exhibit forward where it can best be seen a conical shape, apex downwards. Vessel proceeding under sail when also being propelled by machinery. Same for Inland except that a vessel of less than 12 meters in length is not required to exhibit the dayshape.

Inland Rules

Sailing vessels underway and vessels under oars

(a) A sailing vessel underway shall exhibit:

(i) Sidelights; and

(ii) A sternlight.

(b) In a sailing vessel of less than 20 meters in length the lights prescribed in paragraph (a) of this Rule may be combined in one lantern carried at or near the top of the mast where it can best be seen. Sailing vessel underway—less than 20 meters in length. Same for International.

(c) A sailing vessel underway may, in addition to the lights prescribed in paragraph (a) of this Rule, exhibit at or near the top of the mast, where they can best be seen, two all-round lights in a vertical line, the upper being red and the lower green, but these lights shall not be exhibited in conjunction with the combined lantern permitted by paragraph (b) of this Rule.

(d) (i) A sailing vessel of less than 7 meters in length shall, if practicable, exhibit the lights prescribed in paragraph (a) or (b) of this Rule, but if she does not, she shall exhibit an all-round white light or have ready at hand an electric torch or lighted lantern showing a white light which shall be exhibited in sufficient time to prevent collision.

(ii) A vessel under oars may exhibit the lights prescribed in this Rule for sailing vessels, but if she does not, she shall exhibit an all-round white light or have ready at hand an electric torch or lighted lantern showing a white light which shall be exhibited in sufficient time to prevent collision. Vessel under oars. Same for International.

(e) A vessel proceeding under sail when also being propelled by machinery shall exhibit forward where it can best be seen a conical shape, apex downward. A vessel of less than 12 meters in length is not required to exhibit this shape, but may do so.

The plain-English explanation on this page was written with AI from the regulation text above and checked automatically before publishing: every quote appears in the text, every number comes from it, and a second model confirmed each statement adds nothing the text doesn't say. Regulation text current as of August 12, 2024. The regulation text governs. RegKnot is not affiliated with the U.S. Coast Guard.