- Kylie Masse
- 58.10 second(s)
- Hungary (Budapest)
The fastest swim long course 100 meters backstroke (female) is 58.10 seconds and was achieved by Kylie Masse (Canada) at the 2017 FINA World Championships in Budapest, Hungary, on 25 July 2017.
She became the first Canadian female swimmer to win World Championship gold as a result. The previous record of 58.12 seconds by Gemma Spofforth (UK) had stood since 2009, making it the longest-standing record in women’s swimming at the time.