| Games: | Summer Youth Olympics |
| Games Link: | 2018 Summer Youth Olympics |
| Year: | 2018 |
| Noc: | LCA |
| Nocname: | St. Lucia Olympic Committee |
| Competitors: | 3 |
| Sports: | 2 |
| Location: | Buenos Aires, Argentina |
| Start Date: | 6 |
| End Date: | 18 October 2018 |
| Gold: | 0 |
| Silver: | 1 |
| Bronze: | 0 |
| Rank: | 79 |
| Appearances: | auto |
Saint Lucia participated at the 2018 Summer Youth Olympics in Buenos Aires, Argentina from 6 October to 18 October 2018.
| Athletics | 1 | 1 | 2 | 2 | |
| Swimming | 1 | 0 | 1 | 2 | |
| Total | 2 | 1 | 3 | 4 |
See main article: Athletics at the 2018 Summer Youth Olympics. Saint Lucia qualified two athletes, one male and one female.[1]
| Athlete | Event | Stage 1 | Stage 2 | Total | ||||
|---|---|---|---|---|---|---|---|---|
| Result | Rank | Result | Rank | Total | Rank | |||
| Shelton Keyrine St. Rose | Boys' 100 metres | 11.01 | 10 | 10.70 | 15 | 10.70 | 12 | |
| Julien Alfred | Girls' 100 metres | 11.99 | 2 | 11.23 | 2 | 11.23 | ||
See main article: Swimming at the 2018 Summer Youth Olympics. Saint Lucia qualified one athlete.
| Athlete | Event | Heat | Semifinal | Final | |||
|---|---|---|---|---|---|---|---|
| Time | Rank | Time | Rank | Time | Rank | ||
| Jayhan Odlum-Smith | Boys' 50 metre butterfly | 25.74 | 38 | did not advance | |||
| Boys' 100 metre freestyle | 54.99 | 38 | did not advance | ||||