Vessels sailing under the Puerto Rico Country Flag are required to have on board this flag as part of flag state requirements that derive from maritime regulations in the International Code of Signals and the International Safety Management (ISM) Code. These codes are published by the International Maritime Organization (IMO) as an ongoing effort to reinforce maritime safety procedures and communications to the international maritime community. Fleet management companies and ship owners are responsible to ensure that each vessel in their respective fleets have the appropriate flag signage onboard to be in compliance. This flag is used to identify the flag state a vessel is sailing under and to communicate with other vessels under the provisions of the International Code of Signals.
The Puerto Rico Country Flag is distinguishable by it's five equally proportioned horizontal stripes. These stripes are colored red and white, with red at the top and the bottom. A dark blue isosceles triangle interrupts the stripes at the hoist, or left side, it's base filling the total width of the flag. The point terminates at 1/3 the length of the flag toward the fly, or right side. A white, five pointed star resides in the center of the triangle. The Puerto Rico Country Flag was officially adopted in 1952, and is designated to hold a proportional ratio of 2:3, height to length, respectively. The Puerto Rico Country Flag is not flown, except in the company of the United States Country Flag. The star is meant to represent the Commonwealth of Puerto Rico. The blue triangle represents three branches of government that provide checks and balances to each other in order to limit each branch's power. These are the Judicial, Executive and Legislative branches. Red reminds of the blood that feeds government, and white stands for individual freedom.