| | Top level | Event type
Shortboard, Men – Semi-Finals
| Date | 27 July 2021 — 11:48 | |
|---|---|---|
| Location | Tsurigasaki Surfing Beach, Torami, Chiba | |
| Format | Winners advance to final round. | |
| Head Judge | Glen Elliott |  AUS |
| Head Judge | Richard Pierce |  USA |
| Judge 1 | Luiz Pereira |  BRA |
| Judge 2 | Dan Kosoof |  NZL |
| Judge 3 | Tory Gilkerson | USA |
| Judge 4 | Benjamin Lowe | AUS |
| Judge 5 | Bruno Truch |  FRA |
| Judge 6 | Masato Kato |  JPN |
| Judge 7 | Nuno Trigo |  POR |
Heat #1
| Time | 11:48 |
|---|
| Pos | Competitor | NOC | Points | Best Wave | Second-Best Wave | Wave 1 | Wave 2 | Wave 3 | Wave 4 | Wave 5 | Wave 6 | Wave 7 | ||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | Kanoa Igarashi | JPN | 17.00 | 9.33 | 7.67 | 7.67 | 3.17 | 0.50 | 3.03 | 9.33 | 0.50 | 1.00 | ||
| 2 | Gabriel Medina | BRA | 16.76 | 8.43 | 8.33 | 8.33 | 7.10 | 0.93 | 8.43 | 0.80 | 0.67 | 3.17 |
Heat #2
| Time | 12:24 |
|---|
| Pos | Competitor | NOC | Points | Best Wave | Second-Best Wave | Wave 1 | Wave 2 | Wave 3 | Wave 4 | Wave 5 | Wave 6 | Wave 7 | Wave 8 | Wave 9 | Wave 10 | Wave 11 | Wave 12 | ||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | Ítalo Ferreira | BRA | 13.17 | 6.67 | 6.50 | 1.73 | 4.50 | 1.23 | 1.67 | 1.03 | 6.50 | 1.03 | 1.63 | 1.30 | 6.67 | 1.23 | 1.93 | ||
| 2 | Owen Wright | AUS | 12.47 | 6.47 | 6.00 | 5.00 | 2.57 | 1.00 | 6.00 | 0.43 | 6.47 | 3.70 | 0.37 | – | – | – | – |