What Are Boat Navigation Lights?

At night or in low visibility, boaters must use proper lighting to increase their visibility to all other boats that are on the water.

You can’t afford to take any chances with the safety of your boat. Therefore, knowing what types of boats require navigation lights will help you avoid accidents at night or when visibility is low. With the help of navigation lights, you can see other boats in the area, and they can see you.

The size, speed, and course of virtually any boat can all be deduced from its navigation lights. When approaching another vessel, knowing the configuration and the attributes of its navigation lights can allow you to take any necessary precautions.

Navigation lights aboard ships are required to meet certain standards for their colors (such as white, red, green, yellow, or blue), arc of lighting, range of visibility, and placement location. For practical purposes, this article addresses recreational boats that are under 65 feet in length. There are many reasons why a captain of such a small boat should be familiar with navigation lights.

Keep in mind that lights on your boat must meet the standards described above and below for you to avoid fines and other penalties. At night or in low-visibility conditions, you always need to use the proper lighting. And if there are other boats in your range of vision, you should be familiar with their type and direction.

Boat Navigation Lights

Types of Navigation Lights

Think of the different types of lights on your boat as you might the lights on your car. Lights used for navigation on boats include:

Stern Light

The stern light is at the far rear of the boat. This light will be invisible from the bow of the boat. In technical terms, the stern light must shine in an uninterrupted fashion over a horizon arc of 135 degrees. It’s required to affix the light such that it shines 67.5 degrees from right aft on both sides of the boat.


These lights, typically colored red and green, can be found either on the sides of the boat or, in some cases, on the front. The color red indicates the port side, whereas green indicates the starboard. Sidelights must be bright enough to be seen for at least a mile on a clear night for boats shorter than 39.4 feet. If the boat is longer than 39.4 feet, the sidelights must be visible from a distance of at least 2 miles. Sidelights are required to have a horizon illumination arc of 112.5 degrees.

Combination Lights

For boats less than 65.6 feet in length, a single combination fixture mounted on a vessel’s fore-aft centerline can be used for both sidelights.

Masthead Light

All motorized vessels must be equipped with a white, high-intensity masthead light. The light on the masthead has to shine in a smooth 225-degree arc facing forward over the horizon.

All-Around Light

If your boat’s sidelights go out, it’s crucial that you have a good all-around light so that other vessels can see you. White lights that shine in all directions can be created by centralizing the masthead and stern lights on boats shorter than 39.4 feet. A separate set of masthead and stern lights is required for vessels longer than 39.4 feet.

Lights other than those used for navigation may also be necessary, depending on the type of boat or vessel you have. For example, your local regulations may require that you have a:

Flashing Light

A flashing light is a light that flashes 120 times per minute. Flashing lights are sometimes used by air-cushioned vessels or hovercraft, or they may be used by commercial boats involved in government-authorized public safety events.

Towing Light

A towing light, usually placed at the stern of the boat, is generally mounted on the rear of a boat. The towing light will be located quite close to the stern light and will meet all of the same technical standards as the stern light, except the color will be yellow. This light is used by commercial boats that are pulling or pushing a barge or towing partially submerged objects, such as salvaged vessels or pontoons.

Complying with the Law

From sundown until dawn and in fair and foul weather alike, the correct navigation lights need to be in operation on all boats. No additional lights can be used during these periods if they could possibly be confused with lights required by the federal boating Rules of the Road, if they could obscure the visibility or distinguishing characteristics of your navigation lights, or if they could prevent a proper navigational lookout from being maintained. Navigation lights are required to be used in low-visibility situations and can be used at other times if they’re deemed essential, as per the aforementioned boating Rules of the Road.

For boats less than 65.6 feet in length, please refer to the following summary of visibility and arc of light requirements:

Light Type Required Visible Range in Miles Required Visible Range in Miles Arc of Light in Degrees
(Vessels Less Than 39.4 Feet) (Vessels 39.4 Feet to 65.6 Feet)
Masthead Light 2 3 225
All-Around Light 2 2 360
Sidelights 1 2 112.5
Sternlight 2 2 135

Lights Are Your Responsibility

The person responsible for making sure a boat is equipped with the right navigational lights for its size and the waterways in which it operates is the owner/operator of the boat; it is not a boat’s manufacturer, importer, or dealer. Know that many boats are delivered to dealers or customers without meeting the proper legal requirements as far as their technical characteristics and/or lights being installed in the correct locations as required by law. Keep in mind that the arc of light angles listed above must be satisfied when the boat is in motion as well; if your boat is being driven with a steep bow-up angle, this should be taken into consideration.

Powerboat Navigation Lights

A forward-facing masthead light, sidelights, and a stern light are required for all power-driven boats when they’re underway. A white all-around light and side lights are acceptable for vessels that are smaller than 39.4 feet in length. On the U.S. Great Lakes, power-driven boats don’t need both a masthead light and a stern light, so long as they have one white all-around light.

If at all possible, sailboats that are less than 23 feet in length should be equipped with standard navigational lighting. If this is impractical, the crew on board should still be prepared to avoid an accident or collision by using a flashlight or other lantern with a white beam.

Lights for Diving

A night diving setup is one type of illumination that can be present in tourist areas or in seas where there are wrecks or reefs. With these setups, three vertical lights at the top of a diving boat masthead will alternate between red and white. You should keep your distance from any boats with such lights on them and be on the lookout for divers if you’re close by.

Making Sense of Your Environment

It’s smart to study the basics of navigational lighting, including what kinds of lights are needed and when. However, this is only a starting point. To ensure your safety at night when you’re at sea, you should also familiarize yourself with the meanings of the many navigational lights you’ll see. For example, if you’re in a crossing position and another vessel is approaching with one red light and two white lights, you should quickly realize that you need to yield the right of way to the other vessel, since one light is red.

If you see a green light above a white one, this indicates a fishing boat is trawling. It’s not enough to just stay away from this boat; you also need to know that it can have a huge net out at sea, which you’ll also need to avoid.

It’s essential to be able to rapidly distinguish a wide variety of lights and light combinations, including those for sailboats — which have priority over powered boats — as well as the specialty lights of different fishing vessels, dredging boats, and vessels that aren’t under command. If you want to be a good boater, you need to learn how to navigate from both an observer’s and a boat owner’s perspective. For full boat navigation lights rules, see this guide.