AC長野パルセイロ
After retirement, Yokoyama started coaching career at Omiya Ardija in 2001. He mainly coached for youth team until 2011. In 2012, he moved to Japan Football League club Blaublitz Akita and became a manager. He managed the club 1 season and the club finished at 13th place. In 2013, he moved to Shonan Bellmare and became a coach. In 2016, he moved to J3 League club Tochigi SC. The club won the 2nd place for 2 years in a row (2016-2017) and was promoted to J2 League from 2018. In 2018 season in J2, Tochigi SC finished at the 17th place of 22 clubs and he resigned end of 2018 season. In 2019, he signed with J3 club AC Nagano Parceiro.