COLREGs Rule 22: Minimum visibility ranges of navigation lights

Last reviewed: October 14, 2026

Rule 22 sets the minimum ranges at which the lights prescribed in the Rules must be visible. The ranges depend on the length of the vessel and the type of light. The Inland rule also lists a range for a special flashing light, which the International rule does not list.

Applies toThe section applies to the lights prescribed in these Rules, on vessels of 50 meters or more, 12 meters or more but less than 50 meters, and less than 12 meters in length, and on inconspicuous, partly submerged vessels or objects being towed.

What it says

  1. International: The lights prescribed in these Rules must have the intensity specified in Section 8 of Annex I so they are visible at the minimum ranges the rule lists.

    “The lights prescribed in these Rules shall have an intensity as specified in Section 8 of Annex I to these Regulations so as to be visible at the following minimum ranges:”

  2. Inland: The lights prescribed in these Rules (Subpart C) must have the intensity specified in Annex I (33 CFR part 84) so they are visible at the minimum ranges the rule lists.

    “shall have an intensity as specified in Annex I to these Rules (33 CFR part 84), so as to be visible at the”

  3. International: On a vessel of 50 meters or more in length, a masthead light must be visible at 6 miles.

    COLREGs Rule 22(a)“In vessels of 50 meters or more in length: − a masthead light, 6 miles;”

  4. International: On a vessel of 12 meters or more but less than 50 meters in length, a masthead light must be visible at 5 miles, except that where the vessel is less than 20 meters in length, the range is 3 miles.

    COLREGs Rule 22(b)“a masthead light, 5 miles; except that where the length of the vessel is less than 20 meters, 3 miles;”

  5. Inland: On a vessel of less than 12 meters in length, a masthead light must be visible at 2 miles, a sidelight at 1 mile, and a sternlight at 2 miles.

    COLREGs Rule 22(c)“(i) A masthead light, 2 miles; (ii) A sidelight, 1 mile; (iii) A sternlight, 2 miles;”

  6. Inland: On a vessel of 50 meters or more in length, a special flashing light must be visible at 2 miles.

    COLREGs Rule 22(a)(vi)“(vi) A special flashing light, 2 miles.”

  7. A white all-round light on an inconspicuous, partly submerged vessel or object being towed must be visible at 3 miles.

    COLREGs Rule 22(d)“In inconspicuous, partly submerged vessels or objects being towed: − a white all-round light, 3 miles.”

Common questions

How far must a masthead light be visible on a vessel of 50 meters or more?

A masthead light on a vessel of 50 meters or more in length must be visible at 6 miles. The International and Inland rules give the same range.

“(i) A masthead light, 6 miles;”

What is the masthead light range for a vessel under 20 meters but at least 12 meters long?

For a vessel of 12 meters or more but less than 50 meters, the range is 5 miles, except that where the vessel is less than 20 meters in length, it is 3 miles.

“A masthead light, 5 miles; except that where the length of the vessel is less than 20 meters, 3 miles;”

Does Rule 22 give a visibility range for a special flashing light?

Inland: Yes, a special flashing light must be visible at 2 miles in each length class. The International text does not list a special flashing light.

“(vi) A special flashing light, 2 miles.”

The text of COLREGs Rule 22

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

Rule 22: Visibility of Lights

International (COLREGs)

The lights prescribed in these Rules shall have an intensity as specified in Section 8 of Annex I to these Regulations so as to be visible at the following minimum ranges:

(a) In vessels of 50 meters or more in length: − a masthead light, 6 miles; − a sidelight, 3 miles; − a sternlight, 3 miles; − a towing light, 3 miles; − a white, red, green or yellow all-round light, 3 miles.

(b) In vessels of 12 meters or more in length but less than 50 meters in length: − a masthead light, 5 miles; except that where the length of the vessel is less than 20 meters, 3 miles; − a sidelight, 2 miles; − a sternlight, 2 miles; − a towing light, 2 miles; − a white, red, green or yellow all-round light, 2 miles.

(c) In vessels of less than 12 meters in length: − a masthead light, 2 miles; − a sidelight, 1 mile; − a sternlight, 2 miles; − a towing light, 2 miles; − a white, red, green or yellow all-round light, 2 miles.

(d) In inconspicuous, partly submerged vessels or objects being towed: − a white all-round light, 3 miles.

Inland Rules

Visibility of lights The lights prescribed in these Rules (Subpart C) shall have an intensity as specified in Annex I to these Rules (33 CFR part 84), so as to be visible at the following minimum ranges:

(a) In a vessel of 50 meters or more in length:

(i) A masthead light, 6 miles;

(ii) A sidelight, 3 miles;

(iii) A sternlight, 3 miles;

(iv) A towing light, 3 miles;

(v) A white, red, green or yellow all-round light, 3 miles; and

(vi) A special flashing light, 2 miles.

(b) In a vessel of 12 meters or more in length but less than 50 meters in length:

(i) A masthead light, 5 miles; except that where the length of the vessel is less than 20 meters, 3 miles;

(ii) A sidelight, 2 miles;

(iii) A sternlight, 2 miles;

(iv) A towing light, 2 miles;

(v) A white, red, green or yellow all-round light, 2 miles; and

(vi) A special flashing light, 2 miles.

(c) In a vessel of less than 12 meters in length:

(i) A masthead light, 2 miles;

(ii) A sidelight, 1 mile;

(iii) A sternlight, 2 miles;

(iv) A towing light, 2 miles;

(v) A white, red, green or yellow all-round light, 2 miles; and

(vi) A special flashing light, 2 miles.

(d) In an inconspicuous, partly submerged vessel or object being towed:

(i) A white all-round light, 3 miles.

(ii) [Reserved]

Sections it refers to

  • 33 CFR part 84

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.