Flag of Christmas Island

• green color represents the land;
• blue represents the sea;
• Crux is a constellation of the southern sky centered by four bright stars in the shape of a cross, known as the Southern Cross. It lies at the southern end of the visible range of the Milky Way. The name Crux means cross in Latin;
• the golden boatswain is considered the symbol of the island; 
• the map of the island is green. The yellow disk was originally included only to compensate for the green color of the map, but later it became associated with the mining industry.

In the beginning, the flag of Christmas Island was the Union Jack, i.e. the flag of Great Britain. From 1900 to 1942, the flag was a blue cloth with the flag of the United Kingdom in the canton, the upper left part of the flag, and the coat of arms of the Straits Settlements. 

From 1942 to 1945, the flag of Japan was used, and from 1946 to 1957, the previous version of the blue flag was used, only this time with the coat of arms of Singapore.

Between 1958 and 1986, the flag of Christmas Island was the Australian flag with the Southern Cross. The current flag was unofficially adopted on April 14, 1986 and officially approved on January 26, 2002.