At the 1948 Summer Olympics in London, 11 swimming events were contested, six for men and five for women. All swimming events took place at the Empire Pool. There was a total of 249 participants from 34 countries competing.
Medal table
Medal summary
Men's events
{|
|-
| 100 m freestyle<br>
| || 57.3 (OR)
| || 57.8
| || 58.1
|-
| 400 m freestyle<br>
| || 4:41.0 (OR)
| || 4:43.4
| || 4:47.7
|-
| 1500 m freestyle<br>
| || 19:18.5
| || 19:31.3
| || 19:43.2
|-
| 100 m backstroke<br>
| || 1:06.4
| || 1:06.5
| || 1:07.8
|-
| 200 m breaststroke<br>
| || 2:39.3 (OR)
| || 2:40.2
| || 2:43.9
|-valign="top"
| 4 × 200 metre freestyle relay<br>
| <br />Wally Ris<br />Jimmy McLane<br />Wally Wolf<br />Bill Smith || 8:46.0 (WR)
| <br />Elemér Szatmári<br />György Mitró<br />Imre Nyéki<br />Géza Kádas || 8:48.4
| <br />Joseph Bernardo<br />René Cornu<br />Henri Padou, Jr.<br />Alexandre Jany || 9:08.0
|}
Women's events
{|
|-
|100 m freestyle<br>
| || 1:06.3
| || 1:06.5
| || 1:07.6
|-
| 400 m freestyle<br>
| || 5:17.8 (OR)
| || 5:21.2
| || 5:22.5
|-
| 100 m backstroke<br>
| || 1:14.4 (OR)
| || 1:16.0
| || 1:16.7
|-
| 200 m breaststroke<br>
| || 2:57.2
| || 2:57.7
| || 3:00.2
|-valign="top"
| 4 × 100 metre freestyle relay<br>
| <br />Marie Corridon<br />Thelma Kalama<br />Brenda Helser<br />Ann Curtis || 4:29.2 (OR)
| <br />Eva Arndt<br />Karen Harup<br />Greta Andersen<br />Fritze Carstensen || 4:29.6
| <br />Irma Heijting-Schuhmacher<br />Margot Marsman<br />Marie-Louise Linssen-Vaessen<br />Hannie Termeulen || 4:31.6
|}
Participating nations
249 swimmers from 34 nations competed.