when does the elf on a shelf come

The Elf on the Shelf® tradition begins on December 1st, and the elves arrive at homes around the world to keep an eye on children's behavior. They report back to Santa every night, and on Christmas Eve, they return to the North Pole with the other elves to help with the final preparations for the big night. The tradition has become a beloved and cherished part of many families' holiday celebrations.