Vessels sailing under Croatia 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 flag features three stripes of red white and blue, laying horizontally on top of each other. In the middle of the flag there is the coat of arms of Croatia. This flag was designed to incorporate the colors of the Kingdom of Croatia, which are Red and White along with the colors of the other two kingdoms that make up the nation of Croatia, Slavonia and Dalmatia(which use the colors white and blue and red and blue). The three colors have been used as part of the Croatian flag sicne 1848. The shield of Croatia is featured in the middle of the flag. This shield features a red and white checkered pattern that is meant to represent Croatia. The arms of the five original kingdoms of the area are featured above the shield. These kingdoms include Istria, Dubrovnik, Croatia, Dalmatia, and Slavonia.