The women's 100 metre butterfly competition at the 1999 Pan Pacific Swimming Championships took place on August 22–23 at the Sydney International Aquatic Centre. The last champion was Jenny Thompson of US. This race consisted of two lengths of the pool, all in butterfly. Records Prior to this competition, the existing world and Pan Pacific records were as follows: Results All times are in minutes and seconds. Heats The first round was held on August 22. Semifinals The semifinals were held on August 22. Final The final was held on August 23. References 1999 Pan Pacific Swimming Championships 1999 in women's swimming