The flag of Christmas Island consists of a green and blue background divided diagonally from the lower hoist side to upper fly side. The green triangle occupies the top half of the flag while the blue triangle occupies the bottom half. A golden yellow silhouette of the map of Christmas Island is centered on the flag with a golden yellow disk on the map representing the island's location in the Indian Ocean. The aspect ratio of the flag is 2:3, with the width being twice the height. The specific color codes are:

• Green: #007F4C
• Blue: #1E90FF
• Gold: #FFD700

Overall, the flag has a simple design with bold, contrasting colors and clear geometric shapes.