Navigation lights
What lights to show and what they mean when seen on other vessels. Based on COLREGS (International Regulations for Preventing Collisions at Sea).
Navigation lights must be shown from sunset to sunrise and in restricted visibility. This guide is a quick reference — always consult the full COLREGS for complex or unusual situations.
Related reference
Light colour arcs
| Light | Colour | Arc | Meaning |
|---|---|---|---|
| Masthead / steaming | White | 225° | Power vessel underway, visible from ahead and to each side |
| Starboard sidelight | Green | 112.5° | Right (starboard) side — give way if you see green |
| Port sidelight | Red | 112.5° | Left (port) side — stand on vessel if you see red |
| Sternlight | White | 135° | Rear of vessel — you are behind it |
| All-round white | White | 360° | At anchor, or small vessel |
| All-round red (×2) | Red | 360° | Not under command — keep clear |
| All-round red over white | 360° | Restricted in ability to manoeuvre — keep clear | |
| All-round yellow | Yellow | 360° | Vessel being towed or dredger |
Key rules of thumb
- Red over green = sailing machine — a sailing vessel underway
- Red over white = fishing machine — fishing vessel with gear out, restricted ability to manoeuvre
- Red over red = the captain is dead — not under command, keep well clear
- Green over white = pilot vessel — do not impede
- If you see only a white stern light, you are behind the vessel
- If you see both red and green sidelights, the vessel is coming directly towards you — take avoiding action early
These are memory aids, not substitutes for proper COLREGS knowledge.