| POS | Rank | Heat | BIB | ATHLETE | COUNTRY | RESULTS | ms* | 
|---|---|---|---|---|---|---|---|
| 1 | 1 | 2 | USA | United States U20 | 
 USA                 | 
                3:05.16 Q SB | |
| 2 | 1 | 3 | JPN | Japan U20 | 
 JPN                 | 
                3:07.04 Q SB | |
| 3 | 2 | 3 | IND | India U20 | 
 IND                 | 
                3:08.10 Q NU20R | |
| 4 | 2 | 2 | RSA | South Africa U20 | 
 RSA                 | 
                3:08.84 Q SB | |
| 5 | 3 | 2 | IRL | Ireland U20 | 
 IRL                 | 
                3:08.94 q NU20R | |
| 6 | 4 | 2 | GER | Germany U20 | 
 GER                 | 
                3:08.98 q | .978 | 
| 6 | 3 | 3 | BOT | Botswana U20 | 
 BOT                 | 
                3:08.98 q SB | .978 | 
| 8 | 1 | 1 | AUS | Australia U20 | 
 AUS                 | 
                3:08.99 Q SB | |
| 9 | 2 | 1 | POL | Poland U20 | 
 POL                 | 
                3:10.71 Q | |
| 10 | 3 | 1 | JAM | Jamaica U20 | 
 JAM                 | 
                3:11.30 | |
| 11 | 5 | 2 | GUY | Guyana U20 | 
 GUY                 | 
                3:11.38 NU20R | |
| 12 | 4 | 1 | ESP | Spain U20 | 
 ESP                 | 
                3:11.45 SB | .445 | 
| 13 | 4 | 3 | QAT | Qatar U20 | 
 QAT                 | 
                3:11.45 | .448 | 
| 14 | 5 | 3 | TTO | Trinidad and Tobago U20 | 
 TTO                 | 
                3:11.67 | |
| 15 | 6 | 3 | BRA | Brazil U20 | 
 BRA                 | 
                3:12.68 SB | |
| 16 | 6 | 2 | KSA | Saudi Arabia U20 | 
 KSA                 | 
                3:13.19 SB | |
| 17 | 5 | 1 | GRN | Grenada U20 | 
 GRN                 | 
                3:16.67 | |
| 18 | 6 | 1 | PER | Peru U20 | 
 PER                 | 
                3:17.63 PB | |
| 19 | 7 | 2 | THA | Thailand U20 | 
 THA                 | 
                3:18.81 | |
| 1 | ITA | Italy U20 | 
 ITA                 | 
                DQ | 
ms - Milliseconds - shown when two or more competitors finish with the same time down to hundredths of a second