Navigation Light Guide
A quick-reference guide to boat navigation lights under COLREGS / USCG rules — pick a vessel type, learn the required lights, check visibility ranges, and test yourself with the quiz below.
1. Pick a vessel type
2. Light colors & arcs
Port (red)
112.5° arc, from dead ahead to 22.5° abaft the beam on the port (left) side.
Starboard (green)
112.5° arc, from dead ahead to 22.5° abaft the beam on the starboard (right) side.
Sternlight (white)
135° arc centered on the stern, covering the area the masthead light does not.
Masthead (white)
225° arc, from dead ahead to 22.5° abaft the beam on each side — the forward-facing light on power-driven vessels.
3. Minimum visibility range
| Vessel length | Masthead | Sidelights | Sternlight | All-round |
|---|---|---|---|---|
| Under 12m (39ft) | 2 nm | 1 nm | 2 nm | 2 nm |
| 12m – 20m (39–65ft) | 3 nm | 2 nm | 2 nm | 2 nm |
| 20m – 50m (65–164ft) | 5 nm | 2 nm | 2 nm | 2 nm |
4. When to display navigation lights
🌇 Sunset to sunrise
Required lights must be shown from sunset to sunrise, in all weather, whenever the vessel is underway or anchored.
🌫️ Restricted visibility
Lights must also be shown during fog, haze, heavy rain, or any condition that restricts visibility — even in daylight.
5. Quiz — identify the vessel
Look at each light configuration and pick the vessel type it represents. Score: 0/0