The flag, for use when William is in Canada, was designed and made over a three-month period. It includes the familiar insignia that are on other royal standards, but also has William's "W' cypher at its center.
There is also a red sea shell – symbolizing the family of his late mother Princess Diana – that appears on his official coat of arms.
The flag will, in fact, greet them on their motorcade car that will leave Ottawa's Macdonald-Cartier International Airport after the royal couple land.
It is only the second flag that's been made for use by the British royals in Canada, a Commonwealth country that has Queen Elizabeth as Head of State. The Queen's flag was created in 1962.
William's father Prince Charles also has a new flag, but he won't use that until he visits the country again.
Canadian Press / REX Features / Zuma