She is the first female swimmer and the third overall (after Lars Frölander and Derya Büyükuncu) to participate in six Olympic Games.

In Palma de Mallorca she took a ninth place in the individual 100 m backstroke, swum the prelims in the silver medal winning 4×100 m freestyle team and came fourth in the 4×100 m medley alongside breaststroker Hanna Jaltner, butterfly swimmer Ellenor Svensson and Linda Olofsson on the freestyle leg.

She first appeared on the international scene after the 1994 World Aquatics Championships where she made the semifinals in the 100 m backstroke.

The time in the United States resulted in one individual 1999 Big 12 Conference Women's Swimming and Diving Championships gold medal, on the 100 yard freestyle.

Under her first year she was a part of the Nebraska Cornhuskers Big 12 Conference Women's Swimming and Diving Championships team.

On 17 March 2009, at the Australian Swimming Titles, she broke her own world record in the 50-meter butterfly with a time of 25.44.

FINA, swimming's governing body, had ratified a new rule only 17 days previously that swimmers can only wear one suit.

[16] In June 2016 she became the first female swimmer and the third overall (after Lars Frölander and Derya Büyükuncu) to participate in six Olympic Games.

[17] Alshammar was the flag bearer for Sweden at the opening ceremony of the 2016 Summer Olympics in Rio de Janeiro.