Santa took off from the North Pole at around 6 a.m. ET on Wednesday with Rudolph's red nose guiding the way.
The North American Aerospace Defence Command (Norad), which is responsible for joint air and maritime defence in Canada and the U.S., tracks Santa with a combination of radar, satellites, cameras and fighter jets.
Satellite images available on Norad's website show Santa's minute-by-minute progress. By Wednesday afternoon he had visited New Zealand, Australia, Asia and parts of Africa.
Santa is expected to reach the shores of North America at about 10 p.m. ET, as part of the final leg of his journey around the world. So far, he's delivered nearly three million gifts.
The latest information available from Norad said Santa appeared to be in good spirits and his reindeer are doing fine.