| POS | Rank | Heat | BIB | ATHLETE | COUNTRY | RESULTS | ms* |
|---|---|---|---|---|---|---|---|
| 1 | 1 | 3 | USA | United States U20 |
USA |
3:18.26 Q WU20L | |
| 2 | 2 | 3 | AUS | Australia U20 |
AUS |
3:19.59 Q SB | |
| 3 | 1 | 1 | GBR | Great Britain & NI U20 |
GBR |
3:21.27 Q SB | |
| 4 | 2 | 1 | POL | Poland U20 |
POL |
3:21.47 Q SB | .467 |
| 5 | 1 | 2 | JAM | Jamaica U20 |
JAM |
3:21.47 Q SB | .469 |
| 6 | 3 | 1 | CZE | Czechia U20 |
CZE |
3:21.58 Q NU20R | |
| 7 | 3 | 3 | ESP | Spain U20 |
ESP |
3:21.90 Q PB | |
| 8 | 2 | 2 | RSA | South Africa U20 |
RSA |
3:22.12 Q NU20R | |
| 9 | 3 | 2 | COL | Colombia U20 |
COL |
3:22.14 Q NU20R | |
| 10 | 4 | 2 | GER | Germany U20 |
GER |
3:22.44 SB | |
| 11 | 4 | 1 | IND | India U20 |
IND |
3:22.85 SB | |
| 12 | 5 | 2 | ITA | Italy U20 |
ITA |
3:22.97 NU20R | |
| 13 | 4 | 3 | BEL | Belgium U20 |
BEL |
3:23.26 PB | |
| 14 | 5 | 3 | ECU | Ecuador U20 |
ECU |
3:26.21 SB | |
| 15 | 5 | 1 | MEX | Mexico U20 |
MEX |
3:26.30 | |
| 16 | 6 | 1 | SVK | Slovak Republic U20 |
SVK |
3:29.20 | |
| 17 | 6 | 2 | ZIM | Zimbabwe U20 |
ZIM |
3:34.67 | |
| 18 | 7 | 2 | PNG | Papua New Guinea U20 |
PNG |
3:50.37 PB | |
| 3 | NGR | Nigeria U20 |
NGR |
DQ | |||
| 3 | HUN | Hungary U20 |
HUN |
DQ |
ms - Milliseconds - shown when two or more competitors finish with the same time down to hundredths of a second