The boys' 100 metre freestyle event at the 2018 Summer Youth Olympics took place on 11 and 12 October at the Natatorium in Buenos Aires, Argentina.

[1] The heats were started on 11 October at 10:48.

[2] The semifinals were started on 11 October at 18:22.

[3] The final was held on 12 October at 18:24.

[4]