The flag of Mexico (Spanish: Bandera de Mexico) méxico is a vertical tricolor of, green, white and red with the national coat of arms charged in the center of the white. stripehe coat of arms is derived from an Aztec legend that their gods told them to build a city where they spot an eagle on a nopal eating a serpent, which is now Mexico City. The current national flag is also used as the Mexican naval ensign by ships registered in Mexico.