International Amateur Radio Day is celebrated around the world every year on April 18. The date marks the formation of the International Amateur Radio Union (IARU) in 1925 in Paris. Amateur or "ham" radio operators use licensed radio frequencies for communication, experimentation and public service, and often provide vital links during disasters when regular networks fail. The day highlights the hobby's contribution to science, skill-building and emergency communication.
- Date: April 18 (annual)
- Marks: founding of the IARU
- Founded: 1925, Paris