After retirement, Soejima started coaching career at Kashima Antlers (former "Sumitomo Metal") in 1992. He moved to Gamba Osaka in 1996. In 1998, he returned to Cerezo Osaka (former "Yanmar Diesel") and became a manager in 2000. He was sacked in August 2001. He managed his local club Sagan Tosu in 2002 and Vissel Kobe in 2003. In 2005, he returned to Cerezo Osaka and managed youth team until 2008. He moved to Kataller Toyama and became an assistant coach. In 2010, he moved to Thespa Kusatsu and managed until 2012.