Pieter Timmers (born 21 January 1988) is a Belgian retired competitive swimmer who specialized in sprint freestyle events.

Swimming in lane eight, he blasted a new Belgian record of 48.54 to pick up a matching sixth seed with Cayman Islands' Brett Fraser from the preliminary heats.

[8][9] Followed by the evening session, Timmers fell short in his bid for the final, as he matched a twelfth-place finish with Australia's James Roberts in his semifinal run, outside a record time of 48.57.

Teaming with Dekoninck, Louis Croenen, and Glenn Surgeloose, Timmers anchored the race with a split of 1:48.28 to set a Belgian record of 7:14.44 in the heats.

[12][13] Timmers also solidified his Belgian team (Vanluchene, Grandjean, and Aerents) with a bronze in the 4×50 m freestyle relay, posting a time of 1:25.60.