Marine Navigation Light Buying Guide: What Lights Your Boat Needs and When
Quick answer: A power boat under 12 meters (39.4 ft) needs red (port) and green (starboard) sidelights visible 1 nautical mile and a white light visible 2 miles: either a masthead light plus a sternlight, or a single all-round white light. At anchor you show an all-round white light. Lights must be on from sunset to sunrise and in restricted visibility. Buy USCG-approved lights rated for your boat's length.
Navigation lights are not decoration. They tell other boats what you are, which way you are heading, and whether you are anchored. Running at night with missing or wrong lights is one of the most common causes of collisions, and a quick way to get stopped by the Coast Guard or marine patrol. This guide explains what the rules require for common recreational boats and how to choose and install lights that pass.
Step 1: Know the basic light types
| Light | Color | Arc | Shows |
|---|---|---|---|
| Sidelights | Red to port, green to starboard | 112.5° each, dead ahead to just aft of the beam | Your direction of travel |
| Masthead light | White | 225° forward | A power-driven vessel underway |
| Sternlight | White | 135° aft | Your stern, seen from behind |
| All-round light | White | 360° | Anchored, or replaces masthead plus stern on small boats |
A bi-color light combines both sidelights in one fixture at the bow, which is common on small boats.
Step 2: What a power boat under 12 meters must show
Under the Navigation Rules, a power-driven vessel under 12 meters underway at night shows:
- Sidelights (or a bi-color), visible 1 nautical mile, and
- A masthead light and a sternlight, each visible 2 miles, or
- One all-round white light visible 2 miles in place of the masthead and sternlight.
Most center consoles, bowriders and bass boats use a bow bi-color plus a removable all-round white "pole light" at the stern. The all-round light must be mounted high enough to be seen above the boat's own structure, people and T-tops.
A power boat under 7 meters (23 ft) whose top speed does not exceed 7 knots may show just an all-round white light, with sidelights if practicable.
Step 3: Lights at anchor
When anchored at night, show an all-round white light where it can best be seen. Boats under 7 meters anchored outside a channel, fairway, anchorage or area where other vessels normally navigate are exempt, but showing one is still the safe choice.
Step 4: Sailboats, dinghies and paddle craft
- Sailboats under sail (under 20 m): may combine sidelights and sternlight in one tricolor at the masthead. Once the engine is running, you are a power vessel and must show power-boat lights instead.
- Rowing and paddle craft: must have a white light, such as a flashlight or lantern, ready to show in time to prevent a collision.
Step 5: Choose quality lights
- USCG approval and visibility rating: look for lights rated 1 NM or 2 NM to match the rule for your boat's size.
- LED: uses a fraction of the power of incandescent bulbs and lasts far longer.
- Sealed housings: keep water out. Corroded sockets are the number one cause of nav light failures.
- Portable lights: battery-powered lights are a great fit for dinghies, RIBs, kayaks and as an emergency backup.
Step 6: Install and maintain them
- Mount sidelights so red faces port and green faces starboard, with nothing blocking their arcs.
- Use a dedicated, properly fused circuit and a nav/anchor switch so you can switch between running and anchor modes.
- Coat connections with dielectric grease and check every light before dark.
- Carry spare bulbs or a portable backup light.
Common navigation light mistakes
- A stern pole light that is too short. If the T-top, Bimini or people block the white light from any direction, it is not doing its job.
- Running with the anchor light only. Underway, you need sidelights too. An all-round white light alone tells others you are anchored.
- Corroded sockets. The number one reason lights fail is corrosion at the plug or bulb socket. Clean and grease them every season.
- Bright helm lights. White cockpit lights and a bright chartplotter screen can wash out your nav lights and ruin your night vision. Dim them underway.
- No backup. A portable battery light can keep you legal and visible if a fixed light fails far from the dock.
Our picks
All in stock at Boat Supplies Direct.
Portable all-round white lights (2 NM)
Navisafe Navilight 360 2NM with Rail Mount or the Navisafe All-White 360 2NM with Suction Base, great for dinghies, RIBs and as a backup anchor light.
Portable bow and stern lights for small boats
Innovative Lighting Portable LED Bow Light with the matching Portable LED Stern Light.
Tricolor for small sailboats and inflatables under sail
Navisafe Navilight Tricolor 2NM with Suction Base.
Switch it properly
Bluewater Nav/Anchor Push Button Switch for switching between running and anchor lights.
Frequently Asked Questions
What navigation lights does my boat need?
A power boat under 12 meters needs red and green sidelights plus either a masthead light and sternlight, or a single all-round white light. Sailboats under sail and boats under 7 meters have simpler options.
When do I have to turn on navigation lights?
From sunset to sunrise, and any time visibility is restricted, such as fog or heavy rain.
Which side is the red navigation light on?
Red is on the port (left) side and green is on the starboard (right) side when facing forward.
What light do I show at anchor?
An all-round white light visible from every direction, placed where it can best be seen.
Can I use a tricolor light on a powerboat?
No. A masthead tricolor is only for sailboats under sail. When motoring, a sailboat must show power-vessel lights.
Do kayaks need navigation lights?
Paddle craft must have a white light, such as a flashlight or lantern, ready to show in time to prevent a collision. Many paddlers carry an all-round white light for visibility.
This guide is a general summary of the U.S. Navigation Rules for recreational boats. Always check the current USCG Navigation Rules and your state's regulations for your specific vessel.
