400m Boys Heats, Heat:2 of 4 ; Official result since 19:29
First + 4 fastest to Final
| Rank | Lane | ID | Name | PB | Team | Cat | Result | Info | Video |
| 1 | 2 | 190 | Chen Jian-rong | 51.16 | New Taipei -city | 50.90 | Q | ||
| 2 | 6 | 193 | Jiang Yu-cheng | 50.6 | New Taipei -city | 51.67 | q | ||
| 3 | 4 | 109 | Skorjanc Dominik | 54.43 | Osijek | 53.55 | B | ||
| 4 | 3 | 102 | Webber Bryce | 56.95 | Lake Macquarie | 55.82 | B | ||
| 5 | 7 | 128 | Kanakis Nikolaos | 57 | Evrotas | 1:00.16 | |||
| 5 | 177 | Vidovic Valentin | 54.15 | Maribor | DNS | ||||
| 8 | 205 | Chen Yu-feng | Taoyuan City | DNS |