The women's 100m butterfly events at the 2020 World Para Swimming European Open Championships were held at the Penteada Olympic Pools Complex.
| Rank | Name | Nationality | Time | Notes |
|---|---|---|---|---|
 | Carlotta Gilli |  Italy | 1:03.71 | |
 | Daria Pikalova |  Russia | 1:05.33 | |
 | Alessia Berra | Italy | 1:05.83 | |
| 4 | Joanna Mendak |  Poland | 1:09.74 | |
| 5 | Ariadna Edo Beltrán |  Spain | 1:10.64 | |
| 6 | Róisín Ní Ríain |  Ireland | 1:11.25 | |
| 7 | Marlene Endrolath |  Germany | 1:14.66 |
The European Junior Swimming Championships is an annual swimming competition for European swimmers organized by the Ligue Européenne de Natation and held over five days. The competitor age for females was 15 to 16 years; for males it is 17 to 18 years until 2015. From 2016 the competitor age is for females 14 to 17 years and for males 15 to 18 years.
Nikita Stevie Howarth is a New Zealand para-cyclist and para-swimmer. She became New Zealand's youngest ever Paralympian after being selected for the 2012 Summer Paralympics, aged 13 years 8 months. She again represented New Zealand at the 2016 Summer Paralympics, where she won the gold medal in the women's 200 metre individual medley SM7 and the bronze medal in the women's 50 metre butterfly S7.
Tiffany Thomas Kane, is an Australian Paralympic swimmer. She represented Australia at the 2016 Rio Paralympics, winning a gold and three bronze medals, and at the 2020 Tokyo Paralympics, winning a further two bronze medals.
Nicole Turner, of Portarlington, Laois, is an Irish para-swimmer, competing mainly in the S6, Short Stature category.
Ruby Storm is an Australian Paralympic swimmer with an intellectual disability. She represented Australia at the 2019 World Para Swimming Championships, winning a bronze medal, and at the 2020 Tokyo Paralympics, she won a silver and bronze medal.
