It is a blue ensign containing the Union Flag in the upper left, and on the right, fifteen stars in a ring.

The stars stand for the fifteen islands that make up the Cook Islands (Tongareva, Rakahanga, Manihiki, Pukapuka, Nassau, Suwarrow, Palmerston, Aitutaki, Manuae, Takutea, Atiu, Mitiaro, Mauke, Rarotonga and Mangaia).

A Federal Flag Bill was proposed in the Cook Islands Parliament in 1892, but was not assented to.

The proposed flag had consisted of three horizontal stripes (red, white, red), with a Union Flag in the top left corner, overlaid by a black coconut palm tree on a white circle.

The winner was chosen at a meeting of the cabinet, judging panel and the flag design committee, a green ensign with 15 gold stars in a circle.