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Starboard Side and Port Side Explained

May 29, 2024

No matter where you are in the US, standardized symbols and codes keep boat operators safe and confident in their ability to navigate and communicate effectively.

“Port” and “starboard” are two terms that are used across the nation to refer to the left and right sides of a boat, respectively. Remembering the difference between port and starboard, and their associated navigation light colors, is an important part of responsible boating.

Why learn about port side and starboard side

The main reason we still use the terms port and starboard while boating in the US today is to enable clear communication under all circumstances.

Having standardized terms makes it possible for all people on board to communicate quickly and effectively, obey orders and directions promptly and keep the vessel operating safely. Standardized terms make it possible to:

  • Prevent confusion and avoid collisions when maneuvering boats and ships
  • Guide vessels into position at dock, preventing damage to your boat, other watercraft, and nearby structures. Mooring a boat is difficult enough without communication problems. 

Red and green port and starboard lights are aligned with international standards. These regulations cover all types of navigation lights, so that boaters worldwide can count on understanding navigation signals no matter where they go. They effectively provide a universal language for navigation and safety for maritime authorities.

Port-and-starboardPort is left, starboard is right

The port and starboard sides of your vessel remain the same no matter which way you are facing, but you can figure out which is which by facing the bow.

Port is left

When you are in your boat and facing the bow (front) of your vessel, the left side is your port side.

Starboard is right

When you are in your boat and facing the bow (front) of your vessel, the right side is your starboard side.

Port and starboard lights

The red light indicates the port side on any vessel.

The green light indicates the starboard side on any vessel.

Port and starboard buoys

Port-hand buoys are green, and should be kept on your left (port) when heading upstream. Starboard-hand buoys are red, and should be kept on your right (starboard) when heading upstream. 

Tips for remembering that port is left and starboard is right

The easiest way to remember that port is left is to count the letters in the words “port” and “left”. Four letters each, so they go together!

Trick to remember port is left

That leaves “starboard” and “right”, so they must also go together.


There are other tricks you can use, such as the sentence: Sailors use stars to point them in the right direction after they have left port.

The ship has left port

Or, you can make up your own mnemonic device, as needed.

Why port is red and starboard is green

Using red for port and green for starboard is a tradition with both historical and practical origins. Long ago, red glass was used in lanterns to mark the entrances and boundaries of ports and harbors. Some green glass was also used, though it was harder to come by. This practice gradually evolved to identify red with port and green with starboard. 

Practically speaking, different coloured lights make it easy to distinguish the sides of a vessel, especially in low visibility or at night. As opposite colours, red and green will always be easy to differentiate by persons who do not suffer from either pronatopia (red-blindness) or deuteranopia (green-blindness).

Note: You can still get your boating license if you are red-green colour blind. Even marine captains are only restricted to operating vessels between sunrise and sunset if they are color blind, and a simple boat card is a much easier qualification to acquire than a Captain’s License! 

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