[8] In June 2021, at age 17, Audrey Werro was runner-up in the 800 metres at the Swiss Championships, running 2:02.88 to finish behind champion Lore Hoffmann.

[10] In July, she went to the European Under-20 Championships held in Tallinn, Estonia, where competing against athletes up to two years her senior she won the gold medal for the 800 m.[11] In February 2022, Werro broke the Swiss U23 indoor 400 m record by 0.84 s with a time of 53.03 seconds in Magglingen.

[1] In June, she broke the Swiss U20 and U23 records in the outdoor event, previously held by Delia Sclabas (2:01.29), with a time of 2:00:28 in Geneva.

[14] In August, she won the silver medal in the event at the World U20 Championships held in Cali, Colombia with an U23 national record of 1:59.53, behind Roisin Willis for whom it was also the first time she ran sub-two minutes in an 800 m race.

[20] In July, Werro won her second national title in the outdoor 800 m with a time of 2:01.70 at the 2023 Swiss Championships in Bellinzona.

[26] Shortly after the World Athletics Championships, Werro broke her own national U20 record by running 1:58.13 at the Galà dei Castelli in Bellinzona.