The International Code of Signalling (ICS) is a system for denoting the state of a ship or its equipment by means of flags and lights. It is a complete set of rules and regulations for using the code, which is necessary for obtaining a license for operating a vessel. The ICS was designed to be used by all ship-related authorities, such as the IMO (International Maritime Organization), the U.S. Coast Guard, the British HMG (Her Majesty's Government), the Swedish Transport Administration, and others. The ICS is also widely used by maritime institutions for their own internal use.

This application is an ICS reference tool and contains the following sections:

The first section contains the flags and their meaning.

The second section contains the light-bulb-only flags.