| POS | Rank | Heat | BIB | ATHLETE | COUNTRY | RESULTS |
|---|---|---|---|---|---|---|
| 1 | 1 | 4 | JAM | Jamaica U20 |
JAM |
39.54 Q SB |
| 2 | 1 | 3 | THA | Thailand U20 |
THA |
39.56 Q NU20R |
| 3 | 1 | 1 | KOR | Korea U20 |
KOR |
39.71 Q NU20R |
| 4 | 2 | 1 | FRA | France U20 |
FRA |
39.73 q SB |
| 5 | 2 | 3 | GBR | Great Britain & NI U20 |
GBR |
39.75 q SB |
| 6 | 2 | 4 | TTO | Trinidad and Tobago U20 |
TTO |
39.77 q SB |
| 7 | 3 | 1 | AUS | Australia U20 |
AUS |
39.80 q |
| 8 | 1 | 2 | HKG | Hong Kong, China U20 |
HKG |
39.97 Q |
| 9 | 3 | 3 | GER | Germany U20 |
GER |
40.06 |
| 10 | 2 | 2 | SRI | Sri Lanka U20 |
SRI |
40.14 |
| 11 | 3 | 2 | CHN | PR of China U20 |
CHN |
40.18 |
| 12 | 4 | 1 | ESP | Spain U20 |
ESP |
40.21 |
| 13 | 3 | 4 | NGR | Nigeria U20 |
NGR |
40.28 SB |
| 14 | 4 | 4 | DEN | Denmark U20 |
DEN |
40.31 SB |
| 15 | 5 | 4 | MEX | Mexico U20 |
MEX |
40.34 NU20R |
| 16 | 4 | 2 | ZIM | Zimbabwe U20 |
ZIM |
40.40 NU20R |
| 17 | 4 | 3 | CZE | Czechia U20 |
CZE |
40.41 |
| 18 | 6 | 4 | ITA | Italy U20 |
ITA |
40.44 SB |
| 19 | 5 | 2 | FIN | Finland U20 |
FIN |
40.46 SB |
| 20 | 5 | 1 | GRN | Grenada U20 |
GRN |
40.63 NU20R |
| 21 | 5 | 3 | CAN | Canada U20 |
CAN |
40.70 SB |
| 22 | 7 | 4 | POL | Poland U20 |
POL |
40.99 |
| 23 | 6 | 3 | CHI | Chile U20 |
CHI |
41.62 |
| 24 | 6 | 2 | PER | Peru U20 |
PER |
41.80 SB |
| 25 | 7 | 3 | BUL | Bulgaria U20 |
BUL |
41.92 SB |
| 2 | BRA | Brazil U20 |
BRA |
DNF | ||
| 2 | USA | United States U20 |
USA |
DNF | ||
| 1 | SUI | Switzerland U20 |
SUI |
DNF | ||
| 1 | RSA | South Africa U20 |
RSA |
DQ | ||
| 3 | JPN | Japan U20 |
JPN |
DQ | ||
| 4 | ECU | Ecuador U20 |
ECU |
DNS |