It's really hard to find and apples to apples comparison in practice. The fastest 50m swim on record is 20.91. The fastest underwater dolphin kick, different fr

It's really hard to find and apples to apples comparison in practice. The fastest 50m swim on record is 20.91. The fastest underwater dolphin kick, different from the one in the article, is 23.10 [1]. These aren't super fair comparisons for many reasons but one major one is that the underwater has a slower start. Probably a better comparison is world record for 50m backstroke which is 24.04. I imagine if there were any olympic underwater race (be it fish or dolphin kick), it could probably get close to and possibly overtake the freestyle record, but it would probably take a few years. [1]https://www.youtube.com/watch?v=4EFjQDgIfKM https://www.youtube.com/watch?v=4EFjQDgIfKM