| POS | Rank | Heat | BIB | ATHLETE | COUNTRY | RESULTS | ms* | 
|---|---|---|---|---|---|---|---|
| 1 | 1 | 5 | 1637 | Marco AROP |  CAN | 1:44.56 Q | |
| 2 | 2 | 5 | 2146 | Jesus Tonatiu LOPEZ |  MEX | 1:44.67 Q SB | |
| 3 | 3 | 5 | 1975 | Mark ENGLISH |  IRL | 1:44.76 Q SB | |
| 4 | 4 | 5 | 2011 | Catalin TECUCEANU |  ITA | 1:44.83 q PB | |
| 5 | 1 | 6 | 1507 | Slimane MOULA |  ALG | 1:44.90 Q | |
| 6 | 2 | 6 | 2093 | Wyclife KINYAMAL |  KEN | 1:45.08 Q | |
| 7 | 3 | 6 | 2128 | Abdelati EL GUESSE |  MAR | 1:45.25 Q =SB | |
| 8 | 5 | 5 | 2086 | Noah KIBET |  KEN | 1:45.41 q | |
| 9 | 1 | 2 | 1527 | Peter BOL |  AUS | 1:45.50 Q | |
| 10 | 4 | 6 | 1887 | Daniel ROWDEN |  GBR | 1:45.53 q SB | |
| 11 | 2 | 2 | 1878 | Kyle LANGFORD |  GBR | 1:45.68 Q | |
| 12 | 3 | 2 | 1764 | Mariano GARCÍA |  ESP | 1:45.74 Q | |
| 13 | 6 | 5 | 2300 | Andreas KRAMER |  SWE | 1:45.77 q | |
| 14 | 5 | 6 | 1792 | Tolesa BODENA |  ETH | 1:45.81 q | |
| 15 | 4 | 2 | 1845 | Benjamin ROBERT |  FRA | 1:45.94 q | |
| 16 | 7 | 5 | 1505 | Yassine HETHAT |  ALG | 1:46.05 | |
| 17 | 5 | 2 | 1589 | Abedin MUJEZINOVIĆ |  BIH | 1:46.26 SB | |
| 18 | 1 | 3 | 1847 | Gabriel TUAL |  FRA | 1:46.34 Q | |
| 19 | 1 | 4 | 1508 | Djamel SEDJATI |  ALG | 1:46.39 Q | |
| 20 | 2 | 3 | 2103 | Emmanuel WANYONYI |  KEN | 1:46.45 Q | |
| 21 | 2 | 4 | 2169 | Tony VAN DIEPEN |  NED | 1:46.59 Q | .583 | 
| 22 | 3 | 4 | 2323 | Abdessalem AYOUNI |  TUN | 1:46.59 Q | .589 | 
| 23 | 3 | 3 | 1576 | Eliott CRESTAN |  BEL | 1:46.61 | |
| 24 | 4 | 4 | 1756 | Adrián BEN |  ESP | 1:46.71 | |
| 25 | 6 | 2 | 2361 | Donavan BRAZIER |  USA | 1:46.72 | |
| 26 | 6 | 6 | 2219 | Patryk DOBEK |  POL | 1:46.80 | |
| 27 | 4 | 3 | 2386 | Bryce HOPPEL |  USA | 1:46.98 | |
| 28 | 5 | 4 | 2407 | Brandon MILLER |  USA | 1:47.29 | |
| 29 | 5 | 3 | 2216 | Mateusz BORKOWSKI |  POL | 1:47.61 | .602 | 
| 30 | 6 | 4 | 2267 | Tshepo TSHITE |  RSA | 1:47.61 | .604 | 
| 31 | 7 | 4 | 2203 | Brad MATHAS |  NZL | 1:47.70 | |
| 32 | 6 | 3 | 2015 | Navasky ANDERSON |  JAM | 1:48.37 | |
| 33 | 7 | 2 | 2229 | Patryk SIERADZKI |  POL | 1:48.78 | |
| 34 | 1 | 1 | 2094 | Emmanuel Kipkurui KORIR |  KEN | 1:49.05 Q | |
| 35 | 2 | 1 | 2130 | Elhassane MOUJAHID |  MAR | 1:49.27 Q | |
| 36 | 3 | 1 | 1762 | Álvaro DE ARRIBA |  ESP | 1:49.30 Q | |
| 37 | 4 | 1 | 1797 | Ermias GIRMA |  ETH | 1:49.36 | |
| 38 | 7 | 6 | 2279 | Žan RUDOLF |  SLO | 1:49.87 | |
| 39 | 5 | 1 | 1918 | Marc REUTHER |  GER | 1:50.75 | |
| 40 | 7 | 3 | 1649 | Brandon MCBRIDE |  CAN | 1:57.43 | |
| 41 | 6 | 1 | 2312 | Manuel Belo Amaral ATAIDE |  TLS | 1:58.91 SB | |
| 3 | 2135 | Moad ZAHAFI |  MAR | DQ | |||
| 5 | 2397 | Jonah KOECH |  USA | DQ | |||
| 2 | 1932 | Alex AMANKWA |  GHA | DQ | |||
| 1 | 1859 | Max BURGIN |  GBR | DNS | 
ms - Milliseconds - shown when two or more competitors finish with the same time down to hundredths of a second