The US Coast Guard Flag comes with the Great Seal of the United States over a white background. In the middle of the Seal, an eagle bears a shield with red and white vertical stripes, and a thick horizontal blue stripe. Above is an arc reading "United States Coast Guard"; below is the famous saying "Semper Paratus", which means Always Ready... Beneath the words is the date 1790, which stands for the year when the Revenue Cutter Service, the US Coas Guard predecessor, was founded.
The first flag of Revenue Cutter Service was flown in 1799 to help distinguish its ships from commercial vessels. The ensign had 16 perpendicular stripes, alternate red and white, which matched the number of the states in the Union at that time.
Later the flag's background was changed to white, with a blue eagle and the saying over it. In January 1968, the US Coast Guard Flag was awarded the official status.