[11] The club appointed Masatada Ishii[12] as manager ahead of the 2020–21 Thai League 1 season by releasing Ibson Melo, Kim Pyung-rae, Baworn Tapla, Phumin Kaewta and Woranat Thongkruea.

The club signing Tatsuya Sakai from Montedio Yamagata, Yuto Ono from FC Gifu and Brazilian striker Pedro Júnior.

[19][20] Samut Prakan City advanced to the third round of the Thai FA Cup, being eliminated after losing 1–0 to Muangthong United at the SCG Stadium on 3 February 2021.

[21] In January 2025, The Football Association of Thailand has punished Samut Prakan City by banning them from the league and fining them 2 million baht.

The FA Thailand cited the team's lack of communication and failure to comply with FIFA regulations.