| Rank | Heat | Lane | Name | Nationality | Time | Notes |
| 1 | 9 | 4 | Magnussen, JamesJames Magnussen | Australia | 48.47 | Q |
| 2 | 8 | 4 | McEvoy, CameronCameron McEvoy | Australia | 49.46 | Q |
| 3 | 7 | 4 | Brown, AdamAdam Brown | England | 49.60 | Q |
| 4 | 8 | 6 | Shankland, LeithLeith Shankland | South Africa | 49.64 | Q |
| 5 | 9 | 6 | Carter, DylanDylan Carter | Trinidad and Tobago | 49.72 | Q |
| 6 | 9 | 5 | D'Orsogna, TommasoTommaso D'Orsogna | Australia | 49.73 | Q |
| 7 | 7 | 3 | Kisil, YuriYuri Kisil | Canada | 49.85 | Q |
| 8 | 9 | 3 | Jarvis, CalumCalum Jarvis | Wales | 50.05 | Q |
| 9 | 8 | 3 | Disney-May, JamesJames Disney-May | England | 50.25 | Q |
| 10 | 8 | 7 | Vincent, BradleyBradley Vincent | Mauritius | 50.59 | Q |
| 11 | 7 | 7 | Dunford, JasonJason Dunford | Kenya | 50.60 | Q |
| 12 | 9 | 2 | Coulter, CurtisCurtis Coulter | Northern Ireland | 50.63 | Q |
| 13 | 8 | 1 | Putland, OttoOtto Putland | Wales | 50.66 | Q |
| 14 !=14 | 7 | 5 | Proud, BenjaminBenjamin Proud | England | 50.69 | Q |
| 9 | 7 | Jimmie, ClaytonClayton Jimmie | South Africa |
| 16 | 8 | 5 | Burch, Roy-AllanRoy-Allan Burch | Bermuda | 50.84 | Q |
| 17 | 9 | 1 | Lim, ClementClement Lim | Singapore | 50.93 | |
| 18 | 8 | 2 | Thompson, DavidDavid Thompson | Northern Ireland | 51.15 | |
| 19 | 7 | 6 | Muller, CaydonCaydon Muller | South Africa | 51.27 | |
| 20 | 7 | 8 | Sim, WelsonWelson Sim | Malaysia | 51.51 | |
| 21 | 3 | 2 | Lim Ching Hwang | Malaysia | 51.65 | |
| 22 | 7 | 2 | Yeo, DannyDanny Yeo | Singapore | 51.84 | |
| 23 | 6 | 4 | Gallichan, TomTom Gallichan | Jersey | 52.00 | |
| 24 | 1 | 4 | Atkinson, JevonJevon Atkinson | Jamaica | 52.03 | |
| 25 | 9 | 8 | Munro, MilesMiles Munro | Guernsey | 52.06 | |
| 26 | 6 | 2 | Sau Paea, IfalemiIfalemi Sau Paea | Tonga | 52.76 | |
| 27 | 6 | 5 | Marquet, MathieuMathieu Marquet | Mauritius | 52.94 | |
| 28 | 6 | 3 | Sagor, Mahfizur RahmanMahfizur Rahman Sagor | Bangladesh | 52.97 | |
| 29 | 8 | 8 | Bakhtiarov, AlexandreAlexandre Bakhtiarov | Cyprus | 52.99 | |
| 30 | 6 | 6 | Munn, ConorConor Munn | Northern Ireland | 53.30 | |
| 31 | 6 | 7 | Daniel, JoshuaJoshua Daniel | Saint Lucia | 53.55 | |
| 32 | 5 | 7 | Mohamed, IssaIssa Mohamed | Kenya | 53.96 | |
| 33 | 5 | 4 | Bregazzi, AlexAlex Bregazzi | Isle of Man | 54.00 | |
| 34 | 6 | 1 | Bielich, TomTom Bielich | Isle of Man | 54.01 | |
| 35 | 5 | 6 | Malani, MeliMeli Malani | Fiji | 54.05 | |
| 36 | 5 | 1 | Mogne, IgorIgor Mogne | Mozambique | 54.10 | |
| 37 | 5 | 5 | Sanderson, JamesJames Sanderson | Gibraltar | 54.61 | |
| 38 !=38 | 4 | 5 | Fakir, ShakilShakil Fakir | Mozambique | 55.08 | |
| 6 | 8 | de Silva, CheranthaCherantha de Silva | Sri Lanka | |
| 40 !=40 | 4 | 4 | Clark, WilliamWilliam Clark | Fiji | 55.09 | |
| 5 | 2 | Kawale, StanfordStanford Kawale | Papua New Guinea | |
| 42 | 3 | 1 | Viktora, AdamAdam Viktora | Seychelles | 55.10 | |
| 43 | 5 | 3 | Maina, StevenSteven Maina | Kenya | 55.41 | |
| 44 | 3 | 6 | Jackson, AbeikuAbeiku Jackson | Ghana | 56.47 | |
| 45 | 4 | 6 | Schuster, BrandonBrandon Schuster | Samoa | 56.59 | |
| 46 | 4 | 1 | Jackson, AbbiwAbbiw Jackson | Ghana | 56.87 | |
| 47 | 4 | 2 | Smith, J'airJ'air Smith | Antigua and Barbuda | 57.08 | |
| 48 | 3 | 4 | Ghadiyali, AmmaarAmmaar Ghadiyali | Tanzania | 57.50 | |
| 49 | 1 | 5 | Regis, ChrisChris Regis | Grenada | 57.74 | |
| 50 | 3 | 8 | Shone, MatthewMatthew Shone | Zambia | 57.97 | |
| 51 | 3 | 5 | Khan, SikandarSikandar Khan | Pakistan | 57.99 | |
| 52 | 3 | 7 | Hoffman, DeanDean Hoffman | Seychelles | 58.07 | |
| 53 | 4 | 3 | Hussain, IsrarIsrar Hussain | Pakistan | 58.36 | |
| 54 | 1 | 3 | Hopkin, AndrewAndrew Hopkin | Grenada | 58.50 | |
| 55 | 4 | 8 | Ibrahim, NishwanNishwan Ibrahim | Maldives | 58.74 | |
| 56 | 2 | 4 | Akara, CollinCollin Akara | Papua New Guinea | 59.18 | |
| 57 | 3 | 3 | Sylvester, NikolasNikolas Sylvester | Saint Vincent and the Grenadines | 59.43 | |
| 58 | 2 | 3 | Panuve, Tong LiTong Li Panuve | Tonga | 60.34 !1:00.34 | |
| 59 | 4 | 7 | Adnan, MohamedMohamed Adnan | Maldives | 61.24 !1:01.24 | |
| 60 | 2 | 2 | Halbich, StormStorm Halbich | Saint Vincent and the Grenadines | 61.90 !1:01.90 | |
| 61 | 2 | 7 | Gooding, DillonDillon Gooding | Saint Vincent and the Grenadines | 61.93 !1:01.93 | |
| 62 | 2 | 1 | Dillon, BenBen Dillon | Saint Helena | 61.94 !1:01.94 | |
| 63 | 2 | 6 | Rukundo, PatrickPatrick Rukundo | Rwanda | 63.36 !1:03.36 | |
| 64 | 2 | 5 | Antwi, NanaNana Antwi | Ghana | 99.99 | DNS |
| 65 | 5 | 8 | Cuna, EmidioEmidio Cuna | Mozambique | 99.99 | DNS |
| 66 | 7 | 1 | Lloyd, IeuanIeuan Lloyd | Wales | 99.99 | DNS |