カターレ富山
After retirement, Hirai started coaching career at Kyoto Sanga FC in 2011. He served as goalkeeper coach until 2012. In 2013, he moved to Ehime FC and coached until 2014. In 2015, he returned to Kyoto. In 2017, he moved to Renofa Yamaguchi FC. In 2018, he moved to Kataller Toyama.