| Season | 2021 |
|---|---|
| Dates | Regular season: 13 March – 13 November 2021 Championship: 17–27 November 2021 |
| Champions | Gimpo FC (1st title) |
| Promoted | Gimpo FC |
| Relegated | Pyeongtaek Citizen |
| Matches played | 214 |
| Goals scored | 479 (2.24 per match) |
| Best Player | Kim Jong-seok [1] |
| Top goalscorer | Kim Jong-seok (15 goals) [1] |
← 2020 2022 → | |
The 2021 K3 League was the second season of the K3 League as a semi-professional league. The 15 participating teams played each other twice, and the bottom team was relegated to the K4 League.
Relegated to K4 League
Promoted from K4 League
Withdrawn
| Club | City | Stadium | Capacity |
|---|---|---|---|
| Busan Transportation Corporation | Busan | Busan Gudeok Stadium | 24,363 |
| Changwon City | Changwon | Changwon Football Center | 15,116 |
| Cheonan City | Cheonan | Cheonan Football Center | 15,500 |
| Cheongju FC | Cheongju | Cheongju Stadium | 17,264 |
| Daejeon Korail | Daejeon | Daejeon Hanbat Sports Complex | 17,371 |
| Gangneung City | Gangneung | Gangneung Stadium | 33,000 |
| Gimhae FC | Gimhae | Gimhae Public Stadium | 25,000 |
| Gimpo FC | Gimpo | Gimpo Stadium | 1,024 |
| Gyeongju KHNP | Gyeongju | Gyeongju Civic Stadium | 12,199 |
| Hwaseong FC | Hwaseong | Hwaseong Stadium | 35,270 |
| FC Mokpo | Mokpo | Mokpo International Football Center | 5,952 |
| Paju Citizen | Paju | Paju Public Stadium | 23,000 |
| Pyeongtaek Citizen | Pyeongtaek | Sosabeol Reports Town | 15,000 |
| Ulsan Citizen | Ulsan | Ulsan Stadium | 19,471 |
| Yangju Citizen | Yangju | Godeok Artificial Turf Ground | 5,000 |
| Club | Player 1 | Player 2 | Player 3 | AFC player | Former players |
|---|---|---|---|---|---|
| Changwon City | | ||||
| Cheonan City | | ||||
| Cheongju FC | | ||||
| Gimhae FC | | | | ||
| Gimpo Citizen | | ||||
| Pyeongtaek Citizen | | ||||
| Ulsan Citizen | | | |||
| Pos | Team | Pld | W | D | L | GF | GA | GD | Pts | Qualification or relegation |
|---|---|---|---|---|---|---|---|---|---|---|
| 1 | Cheonan City | 28 | 16 | 6 | 6 | 50 | 25 | +25 | 54 | Qualification for Championship final |
| 2 | Gimpo FC (C, P) | 28 | 14 | 10 | 4 | 35 | 20 | +15 | 52 | Qualification for Championship semi-final and K League 2 |
| 3 | Mokpo City | 28 | 14 | 8 | 6 | 34 | 23 | +11 | 50 | Qualification for Championship first round |
| 4 | Gyeongju KHNP | 28 | 13 | 7 | 8 | 39 | 30 | +9 | 46 | |
| 5 | Gimhae FC | 28 | 12 | 8 | 8 | 39 | 35 | +4 | 44 | |
| 6 | Busan Transportation Corporation | 28 | 11 | 8 | 9 | 32 | 33 | −1 | 41 | |
| 7 | Ulsan Citizen | 28 | 9 | 11 | 8 | 32 | 24 | +8 | 38 | |
| 8 | Changwon City | 28 | 9 | 11 | 8 | 28 | 27 | +1 | 38 | |
| 9 | Daejeon Korail | 28 | 8 | 12 | 8 | 32 | 30 | +2 | 36 | |
| 10 | Paju Citizen | 28 | 8 | 11 | 9 | 32 | 36 | −4 | 35 | |
| 11 | Cheongju FC | 28 | 9 | 7 | 12 | 37 | 39 | −2 | 34 | |
| 12 | Hwaseong FC | 28 | 8 | 10 | 10 | 29 | 34 | −5 | 34 | |
| 13 | Gangneung City | 28 | 4 | 8 | 16 | 23 | 42 | −19 | 20 | |
| 14 | Yangju Citizen | 28 | 4 | 8 | 16 | 17 | 43 | −26 | 20 | |
| 15 | Pyeongtaek Citizen (R) | 28 | 5 | 7 | 16 | 20 | 38 | −18 | 2 | Relegation to K4 League |
When the first round and semi-final matches were finished as draws, their winners were decided on the regular season rankings without extra time and the penalty shoot-out.
| First round | Semi-final | Final | ||||||||||||||
| 2 | Gimpo FC | 2 | ||||||||||||||
| 3 | Mokpo City | 0 | ||||||||||||||
| 3 | Mokpo City | 1 | ||||||||||||||
| 4 | Gyeongju KHNP | 1 | ||||||||||||||
| Gimpo FC | 1 | 2 | 3 | |||||||||||||
| 1 | Cheonan City | 0 | 2 | 2 | ||||||||||||
| Mokpo City | 1–1 | Gyeongju KHNP |
|---|---|---|
|
|
| Gimpo FC | 2–0 | Mokpo City |
|---|---|---|
| Son Seok-yong |
| Gimpo FC | 1–0 | Cheonan City |
|---|---|---|
| Yoon Min-ho |
| Cheonan City | 2–2 | Gimpo FC |
|---|---|---|
| Report |
|
Gimpo FC won 3–2 on aggregate.