Letters traveling from Japan to the United States arrive within five to 10 days when sent via standard mail. Japan Post, the postal system of Japan, also offers express mailing options for customers who wish to send a letter more quickly.
The exact delivery time for letters traveling from Japan varies based on where the letter originates. The final destination of the international letter within the United States also affects the delivery time frame. After the letters enter the United States, the U.S. Postal Service delivers them on behalf of the Japanese postal service. Standard letters travel across the country as First-Class Mail.