They are both correct and used every day, the meaning is the same (at the event of arriving). I would say “upon” is slightly more correct, or slightly more formal. I hear both used all the time.

What does it mean upon arrival?

Definition of Upon arrival. when something shows up, comes or appears. Examples of Upon arrival in a sentence. 1. “ Your luggage will be waiting at the baggage claim upon arrival of your airplane,” the flight attendant explained to the passengers.

How do you use upon arrival?

Upon arrival my attention was directed to a wooden door on the western side of the building. Upon arrival at the destination there will be one set of skis or a snowboard for each team. Upon arrival everything was going right, all my worries slowly eroded away.