| Club: | FC Cartagena |
| Season: | 2020–21 |
| Chrtitle: | President |
| Chairman: | Paco Belmonte |
| Mgrtitle: | Head coach |
| Manager: | Borja Jiménez |
| Stadium: | Cartagonova |
| League: | Segunda División |
| League Result: | 16th |
| Cup1: | Copa del Rey |
| Cup1 Result: | First round |
| Pattern La1: | _fccartagena2021h |
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| Pattern La2: | _fccartagena2021a |
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| Prevseason: | 2019–20 |
| Nextseason: | 2021–22 |
The 2020–21 season was Fútbol Club Cartagena's 26th season in existence and the club's first season back in the second division of Spanish football. In addition to the domestic league, Cartagena participated in this season's edition of the Copa del Rey. The season covered the period from 26 July 2020 to 30 June 2021.
See main article: FC Cartagena B.
See main article: 2020–21 Segunda División.
The league fixtures were announced on 31 August 2020.[1] [2]
See main article: 2020–21 Copa del Rey.