Advancing to the senior ranks, Arikawa/Miyamoto competed at their first Grand Prix events and became the national silver medalists in the 1998–1999 season.

In the 2001–2002 season, Arikawa/Miyamoto won their first senior national title and then placed 8th at the Four Continents Championships in Jeonju, South Korea.

In February 2003, they won the bronze medal at the Asian Winter Games in Aomori, Japan, and placed 8th at their final competition, the Four Continents Championships in Beijing, China.

During their three-season partnership, they competed together at six Grand Prix events and placed in the top ten at three Four Continents Championships.

[5] He has choreographed for: Additionally, Miyamoto has his own TV segment titled, KENJI's Room, on the J Sports channel, where he conducts interviews with fellow Japanese figure skaters.