I don’t have live access to the latest updates right now. Here’s what’s recently notable in the 100m backstroke world records:
- For long course (short in meters, 50m pool): Regan Smith and Kaylee McKeown have traded world-best times in recent years, with Smith frequently challenging and equaling records in various meets, though the current official long-course world record time is held by Kaylee McKeown as of mid-2024, and Smith has matched or approached near-records in later World Cup events.[4][7]
- For short course (25m pool): Regan Smith and Kaylee McKeown have both set and approached short-course records in 2024–2025 World Cup stops, with Smith notably equalling or breaking times around the mid-54s range for women in the 100m backstroke.[10][4]
If you want, I can look up the exact latest timestamped world record in both long course and short course, and provide sources. Would you like me to do that and also include a quick summary of the current record holders by gender and course?