See main article: 2020–21 Billie Jean King Cup Europe/Africa Zone. The play-offs of the 2021 Billie Jean King Cup Europe/Africa Zone Group III were the final stages of the Group III zonal competition involving teams from Europe and Africa. Using the positions determined in their pools, the twenty-one teams faced off to determine their placing in the 2021 Billie Jean King Cup Europe/Africa Zone Group III. The top two teams advanced to Billie Jean King Cup Europe/Africa Zone Group II.
| Placing | Pool A | Pool B | Pool C | Pool D | Pool E | Pool F |
|---|---|---|---|---|---|---|
| 1 | ||||||
| 2 | ||||||
| 3 | ||||||
| 4 | colspan=3 | |||||
The first placed teams of each pool were drawn in head-to-head rounds. The winners advanced to Group II in 2022.
The second placed teams of each pool were drawn in head-to-head rounds to find the equal 7th placed teams.
The third placed teams of each pool were drawn in head-to-head rounds to find the equal 13th placed teams.
The fourth placed teams of each pool were drawn in head-to-head rounds to find the 19th placed team.
| Placing | Teams | ||
| Promoted/First | |||
| Third | |||
| Fifth | |||
| Sixth | |||
| Seventh | |||
| Ninth | |||
| Eleventh | |||
| Twelfth | |||
| Thirteenth | |||
| Fifteenth | |||
| Seventeenth | |||
| Eighteenth | |||
| Nineteenth | |||
| Twentieth | |||
| Twenty-first | |||