Jonny Kulow Swims 48.70 100 Free to Become Fastest American This Season; #2 17-18 Ever


  • June 2-4, 2023
  • Mona Plummer Aquatic Center, Tempe, Arizona
  • Long Course Meters (50m)
  • Psych Sheets
  • Results on Meet Mobile “2023 Sun Devil Open”

After swimming a personal best in prelims to become the fourth fastest swimmer in the 17-18 age group ever, Jonny Kulow swam even faster in finals winning the 100 free in a 48.70. Kulow now moves up to the second fastest ever, 0.01 seconds off the national age group record. Jack Alexy holds the NAG record in a 48.69.

Kulow also moves up to become the fastest American in the event so far this season. Ryan Held who also trains at Arizona State was second to Kulow tonight in a 48.88, just off his season best of 48.74. Kulow has now dropped over a second and a half off his personal best this season as his best prior to this season was a 50.39 from 2021 Wave II US Olympic Trials.


  1. Jonny Kulow, 48.70
  2. Matt King, 48.72
  3. Ryan Held, 48.74
  4. Hunter Armstrong, 48.79
  5. Kaii Winkler, 48.81
  6. Jack Alexy, 48.85
  7. Drew Kibler 48.89

Winning the women’s 100 free was Olivia Smoliga who swam a 54.54. Smoliga has been consistently posting 54-mid times this season in the event. She has been a 55.08 or faster in nine out of ten of her swims this calendar year (with the lone exception of prelims this morning when she swam a 56.71). Smoliga’s season best of 54.37 from Pro Swim-Westmont makes her the seventh fastest American so far this season.

Both Chase Kalisz and Alex Colson shined in the men’s 200 fly. Kalisz won in a 1:56.34, just off his season best of 1:56.03 which he swam at Pro Swim-Fort Lauderdale. That time makes him the second fastest American this season. Finishing behind Kalisz was Colson who swam a 1:57.87. Colson has a best time of 1:56.50 which he swam in prelims at 2022 International Team Trials. Colson went on to finish seventh in a 1:56.98.

Rising Arizona State sophomore Andy Dobrzanski won the men’s 200 breast in a 2:13.91. Dobrzanski improved upon his personal best that he set three weeks ago during prelims. His personal best coming into this summer was a 2:19.69.

Other event winners:

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Alex Wilson
3 months ago

I note that according to meet manager Jonny did a negative split of 25.65 followed by 23.05 equals 48.70. In his earlier 50 free swim he did 23.05 So the second half of his hundred was as fast as his 50!

Winter Apple
Reply to  Alex Wilson
3 months ago

I can’t tell if this is serious but NO, he did not come back in a 23.0, that would be the fastest 2nd 50 ever by a wide margin.

Alex Wilson
Reply to  Winter Apple
3 months ago

After further analysis I agree. Since I was at the meet I think that the manual triggered not pad triggered 50 split time may be in error, although the total time is completely electronic and accurate. I attended the meet and there were electronic timing pads at only the east end of the pool.

Reply to  Alex Wilson
3 months ago

Not true, pads were on both ends

Alex Wilson
3 months ago

And Jonny, still only 18, just finished his freshman year with the ASU Sun Devils! He will be even more awesome in the upcoming season!

3 months ago

Wasn’t just Kulow in the 100 Free: there were 5 under 50 seconds.

Kulow -PB Held :49.20, Sammon :49.37PB, Dolan :49.79PB, Swift :49.81 (he won’t be in final as he is traveling back to New Zealand to finalize Fukuoka prep), plus Kos :50.05PB(Prior PB :51.65), Xander Skinner, Namibia, :50.23 PB, which doesn’t even include Grant House who was :50.72. Swift not returning allows a 17 year old into the final, Ian Pickles at :51.13. Beyond this ther were 4 more at :51.50 or better.

The 200 Fly Women is very interesting; Regan Smith, Olympic Silver and #1 American for the year going into the meet at 2:07.92 … was the #3 seed. #2 seed Lindsay Looney, Pac-12 Champ and 4th… Read more »

3 months ago

Best times of the day in 100 Free:

Jonny Kulow: :48.70 PB (Current #1 in US)
Ryan Held: :48.88 (this time would be #5 were it not for his 2nd ranked :48.74)
Patrick Sammon :48.93 PB (Article stopped list at Drew Kibler 7th; this swim by Sammon is 8th)
Jack Dolan :49.79 PB prelim
Carter Swift :49.81 prelim (withdrew from final as he was leaving for New Zealand for final Fukuoka prep)
Hubert Kos :50.05 PB prelim (slowed in final after :1:57.25 200 Back earlier in session)
Julian Hill :50.08 PB, winning B Final: (prior best :50.60 Wave II Olympic Trials)
Grant House :50.23 (PB 49.24 Wave II Olympic Trials; PSS-Westmont SB :50.20)… Read more »

3 months ago

Look at all those youngsters in the top 6!

3 months ago

Nice. Wonder if he can get to under 48 this year. Likely not but the progress is clear. 48 low would be amazing

Alex Wilson
Reply to  Swim2win
3 months ago

If you look at his splits, see my post above, He should be able to lower his times. His second half time in the 100 was the same as his 50 time at 23.05. The total of the 50 time and the 100 time 2nd half would be 46.10! So we shall see what he can do. I think a 47 is possible. He certainly has the speed.

3 months ago

Wow. Kulow is gonna be a factor in the Paris 4×1 relay 🔥

Swim Alchemist
3 months ago

.01 off the NAG! Hope he has another chance.

Reply to  Swim Alchemist
3 months ago

i heard he is swimming at summer juniors this year. rip to everyone attending🙏🏽

Reply to  swammer
3 months ago

Well there’s a kid who was 49.0 at 15 that’s gonna be there. And another kid who is 48.8 2 years younger than this guy as well

Reply to  Swim2win
3 months ago

Jrs this year is gonna be historically fast in every event.

Summer is Titmus’ Sleep Paralysis Demon
Reply to  swammer
3 months ago

Don’t count your chickens….

About Anya Pelshaw

Anya Pelshaw

Anya has been with SwimSwam since June 2021 as both a writer and social media coordinator. She was in attendance at the 2022 and 2023 Women's NCAA Championships writing and doing social media for SwimSwam. Currently, Anya is pursuing her B.A. in Economics and a minor in Government & Law at …

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