Riku first appears in the U.S. registration record in 1996. Its popularity climbed over the following decades. In 2024, 24 babies received the name (ranked #4391). Today it sits well outside the top 1,000 (around #5239), with roughly 19 babies named Riku each year. Riku's usage has held roughly steady recently. In total, around 470 babies have been registered with this name since 1880.