Schoolchildren from the tsunami-hit areas in northern Japan presented each athlete in the country's 518-member delegation with a hand-carved good luck charm made of driftwood during a send-off ceremony in Tokyo over the weekend.
The medals measure 5 centimetres (2 inches) in diameter and have the Japanese Olympic Committee emblem on them. The attached ribbons carry signed messages from the children.
The March 11, 2011 disasters left about 19,000 people dead or missing.
One of the medal carvers, 14-year-old Mizuho Sato, said many people supported her after the tsunami and that it's now her turn to cheer for the athletes.
That brought tears to the eyes of javelin thrower Yukifumi Murakami, who vowed to return the favour with good results.