The 2021–22 season is Samut Prakan City's 3rd consecutive seasons in top flight after the owner decided to change the club's name from Pattaya United to Samut Prakan City and relocated it to Samut Prakan Province in 2018.

[1] In this season, Samut Prakan City participates in 3 competitions which consisted of the Thai League, FA Cup, and League Cup.

The season was supposed to start on 31 July 2021 and concluded on 21 May 2022.

[2] Then, due to the situation of the COVID-19 pandemic is still severe, FA Thailand decided to postpone the season to start on 13 August 2021 instead.

Therefore, FA Thailand decided to postpone the opening day for the second time to start on 3 September 2021.