| POS | Rank | Heat | BIB | ATHLETE | COUNTRY | RESULTS | ms* |
|---|---|---|---|---|---|---|---|
| 1 | 1 | 4 | 460 | Moitalel Mpoke Naadokila |
 KEN |
50.87 Q PB | |
| 2 | 1 | 3 | 144 | Rasheeme Griffith |
 BAR |
51.02 Q SB | |
| 3 | 2 | 4 | 175 | Alison dos Santos |
 BRA |
51.08 Q | |
| 4 | 1 | 2 | 294 | Alastair Chalmers |
 GBR |
51.16 Q | |
| 5 | 1 | 5 | 555 | Sokwakhana Zazini |
 RSA |
51.21 Q | |
| 6 | 2 | 5 | 306 | Alex Knibbs |
GBR |
51.29 Q | |
| 7 | 3 | 4 | 583 | Carl Bengtström |
 SWE |
51.35 Q | |
| 8 | 4 | 4 | 336 | Ierotheos Dritsas |
 GRE |
51.39 q PB | |
| 9 | 1 | 6 | 427 | Malik James-King |
 JAM |
51.54 Q | |
| 10 | 2 | 2 | 400 | Alessandro Sibilio |
 ITA |
51.59 Q SB | |
| 11 | 3 | 2 | 574 | Julien Bonvin |
 SUI |
51.64 Q PB | |
| 12 | 2 | 3 | 428 | Leonardo Ledgister |
JAM |
51.65 Q | |
| 13 | 3 | 3 | 647 | Quivell Jordan |
 USA |
51.75 Q | |
| 14 | 4 | 3 | 244 | Aleix Porras |
 ESP |
51.83 q | |
| 15 | 4 | 2 | 496 | Ramsey Angela |
 NED |
51.95 | |
| 16 | 5 | 4 | 143 | Nathan Fergusson |
BAR |
52.02 q PB | |
| 17 | 2 | 6 | 439 | Yusuke Shirao |
 JPN |
52.09 Q | |
| 18 | 1 | 1 | 655 | Cory Poole |
USA |
52.12 Q | |
| 19 | 3 | 5 | 229 | Jesús David Delgado |
ESP |
52.13 Q | |
| 20 | 6 | 4 | 379 | Mahdi Pirjahan |
 IRI |
52.18 q | |
| 21 | 5 | 3 | 488 | Ismail Manyani |
 MAR |
52.24 q | |
| 22 | 2 | 1 | 540 | Bassem Hemeida |
 QAT |
52.35 Q | .342 |
| 23 | 3 | 1 | 554 | Lourens Steenekamp |
RSA |
52.35 Q | .346 |
| 24 | 3 | 6 | 349 | Boaz Madeus |
 HAI |
52.38 Q | |
| 25 | 4 | 1 | 433 | Hayata Goto |
JPN |
52.48 | |
| 26 | 4 | 5 | 258 | Gadisa Bayu |
 ETH |
52.59 | |
| 27 | 4 | 6 | 401 | Samuele Licata |
ITA |
52.60 | |
| 28 | 5 | 5 | 312 | Emil Agyekum |
 GER |
52.70 | |
| 29 | 5 | 1 | 251 | Karl Erik Nazarov |
 EST |
52.80 | |
| 30 | 5 | 6 | 195 | Jiahao Fu |
 CHN |
52.82 PB | |
| 31 | 5 | 2 | 459 | James Mucheru |
KEN |
52.88 | |
| 32 | 6 | 3 | 116 | Harvey Murrant |
 AUS |
53.02 | |
| 33 | 6 | 2 | 352 | Dániel Huller |
 HUN |
53.13 | |
| 34 | 7 | 3 | 274 | Vesa Kittilä |
 FIN |
53.21 PB | |
| 35 | 6 | 5 | 112 | Damián Moretta |
 ARG |
53.43 | |
| 36 | 7 | 5 | 602 | Fahd Benammar |
 TUN |
53.71 | |
| 37 | 7 | 4 | 185 | Nathaniel St. Romain |
 CAN |
53.85 | |
| 38 | 6 | 1 | 584 | Anton Bertilsson |
SWE |
54.82 | |
| 39 | 7 | 1 | 135 | Branson Rolle |
 BAH |
1:08.85 | |
| 6 | 674 | Norman Mukwada |
 ZIM |
DQ | |||
| 6 | 328 | Justus Ringel |
GER |
DQ | |||
| 2 | 490 | Sergio Armando Esquivel |
 MEX |
DNF |
Legend
ms - Milliseconds - shown when two or more competitors finish with the same time down to hundredths of a second