How to use boat lights as signals for safe navigation at night

There is something special and exciting about boating at night. It’s quiet, calm, and there is typically less traffic. Of course, boating at night also poses a big challenge that you don’t face during daylight: visibility. Boating at night not only makes it harder to see your course, it also impacts your ability to communicate with other boaters.

If you understand how to use and interpret certain boat light signals, however, you’ll find yourself more confident and capable of boating at night. Below, you’ll find some of the most common light signals used by boaters at night.

Also Read: How to Boat Safely in the Fog


A sternlight is one of the easiest signals to interpret and one of the most common you’ll see. A sternlight is a while light that shines behind or on the rear a boat. If you see that light, it means you are overtaking another boat and need to adjust your speed or give way.

Masthead light

Required by all motorized boats, the masthead light illuminates forward and to the sides of the boat. Masthead lights must be visible from at least two miles away and across 225 degrees. When the motor is running, this light must be displayed. If you don’t see a masthead light but notice a vessel, it is likely a sailboat.


Also known as combination lights, sidelights are red and green and are a clear indication that you are approached another vessel from the side or head on. A red light means you are approaching from the left side (port) and a green light means you are approaching from the right side (starboard).

All Around White Light

Shining directly above the boat, this light should shine at a 360 degree arc over the horizon. This light makes it apparent whether or not a boat is moving. The all-around light should be visible from all angles and serves as a visible anchor.

Understanding these lights is essential for nighttime boating, but it’s important to note that other boaters may not know the meaning behind these lights, so a little extra caution is advised.