Athletes with a visual impairment are classified into three classes, according to the degree of vision loss: S11 for athletes with no sight to class S13 for legally blind. The following events are offered at the Paralympic Games for these athletes:

50m, 100m and 400m Freestyle

100m Backstroke

100m Breaststroke

100m Butterfly

200m Individual Medley

4x100m Freestyle Relay and 4x100m Medley Relay.

In the case of swimmers with a physical disability, classification is based on several factors ie, muscle strength, movement co-ordination, joint range of movement and/or limb length. The swimmers are also required to perform a practical water session, performing all strokes and accordingly assessed on their ability

After the assessment is completed, athletes are classified as follows:

10 classes (S1-S10) in Freestyle, Backstroke and Butterfly

10 classes (SM1-SM10) for Individual Medley, and

9 classes (SB1-SB9) in Breaststroke.

The higher the number of the class, the lower the disability, eg, class 1 is for athletes with a severe disability and class 10 for athletes with a minimal disability.

Depending on the classification of athletes with a physical disability, the following events are offered at the Paralympic Games:

50m and 100m Freestyle: class S1 to S10

200m Freestyle: class S1 to S5

400m Freestyle: class S6 to S10

50m Backstroke: class S1 to S5

100m Backstroke: class S6 to S10

50m Butterfly: class S1 to S7

100m Butterfly: class S8 to S10

50m Breaststroke: class SB1 to SB3

100m Breaststroke: class SB4 to SB9

150m Individual Medley: class SM1 to SM4

200m Individual Medley: class SM5 to SM10

Relay 4x50m Freestyle and 4x50 Medley Relay

Relay 4x100m Freestyle and 4x100m Medley Relay

(BOCOG)