| POS | BIB | ATHLETE | COUNTRY | MARK | Reaction Time | 
|---|---|---|---|---|---|
| 1 | 173 | Karabo SIBANDA |  BOT | 45.15 Q PB | 0.156 | 
| 2 | 904 | Kahmari MONTGOMERY |  USA | 45.71 Q | 0.166 | 
| 3 | 236 | Anthony José ZAMBRANO |  COL | 45.81 q PB | 0.183 | 
| 4 | 570 | Naoki Kitadani |  JPN | 46.41 q PB | 0.162 | 
| 5 | 208 | Jamal Walton |  CAY | 46.61 | 0.155 | 
| 6 | 531 | Sean BAILEY |  JAM | 47.09 | 0.164 | 
| 7 | 492 | Taha Hussein YASEEN |  IRQ | 47.26 | 0.180 | 
| 8 | 499 | Vladimir ACETI |  ITA | 47.41 | 0.240 | 
| POS | BIB | ATHLETE | COUNTRY | MARK | Reaction Time | 
|---|---|---|---|---|---|
| 1 | 748 | Abdalelah Haroun |  QAT | 45.55 Q | 0.180 | 
| 2 | 571 | Kazuki Matsukiyo |  JPN | 46.69 Q PB | 0.139 | 
| 3 | 654 | Iván Núñez |  MEX | 47.00 | 0.143 | 
| 4 | 658 | Jochem DOBBER |  NED | 47.22 | 0.159 | 
| 5 | 265 | Luis Charles |  DOM | 47.33 | 0.206 | 
| 6 | 588 | Edwin Ngeeti |  KEN | 47.51 | 0.193 | 
| 171 | Baboloki THEBE |  BOT | DQ R163.3(a) | 0.169 | |
| 191 | Musa ISAH |  BRN | DNS | 
| POS | BIB | ATHLETE | COUNTRY | MARK | Reaction Time | 
|---|---|---|---|---|---|
| 1 | 589 | Geoffrey Kiprotich |  KEN | 45.38 Q PB | 0.192 | 
| 2 | 899 | Wilbert LONDON |  USA | 45.49 Q | 0.144 | 
| 3 | 365 | Cameron CHALMERS |  GBR | 46.51 PB | 0.218 | 
| 4 | 541 | Christopher TAYLOR |  JAM | 46.60 | 0.225 | 
| 5 | 223 | Yu Ang WU |  CHN | 46.83 | 0.179 | 
| 6 | 715 | Tymoteusz ZIMNY |  POL | 47.14 PB | 0.165 | 
| 7 | 193 | Myles Banfield |  CAN | 47.46 | 0.160 | 
| 8 | 237 | David Å alamon |  CRO | 47.51 PB | 0.157 |