Pan-Pac Roster Update: Shackell, Mathias Jump On With Only World Junior Champs Left

2025 U.S. Summer Championships

• Tuesday, August 5 – Friday, August 8, 2025
• Irvine, California
• William Woollett Aquatics Center
• Start Times
  • Prelims: 9:00 am local / 12:00 pm ET
  • Finals: 5:00 pm local / 8:00 pm ET
• LCM (50 meters)
• Meet Central
• Psych Sheets
• Live Results
• Live Stream Info (Available on USA Swimming Network App)
• Live Recaps
  • Prelims: Day 1 | Day 2 | Day 3
  • Finals: Day 1 | Day 2 | Day 3

With the conclusion of the 2025 US Summer Championships, next years Pan-Pacific Roster is just one meet away from completion, as the 2025 World Junior Championships serves as the fifth and final qualifying opportunity for the team. This year USA Swimming has opted for a different selection procedure in part due to the changes over the past five years and Van Mathias and Aaron Shackell took advantage of the change with each adding their name to the roster, (provisionally in the case of Shackell).

Mathias, who returned to competition this summer after two years off shocked the field in the 50 Breast setting a new Pro Swim Series record of 26.76, a time that vaulted him to the top of the rankings of Americans this year. Shackell, a 2024 Paris Olympian in the 400 free had a big rebound from his poor performance at the US Nationals as he won the 400 free in Irvine in a time of 3:45.03, a new personal best by .42 and surpassing the 3:45.71 put forth by Luka Mijatovic at the US Nationals.

Skip Down to Pan-Pac Rosters at Present if you do not wish to read about the recent history of selection procedures in regards to USA Swimming. 

Since the disruption caused by the COVID-19 Pandemic, USA Swimming has run a gauntlet of meets over the past four years. From 2022 to 2024, there were three World Championships and of course the Paris Olympics. However, this year has seen a return to a normal global meet schedule as this year held (or is about to hold) its normally scheduled World University Games, World Championship and Junior World Championships, with each of these meets having their roster selected from the same meet, the 2025 US Nationals.

With the Pan-Pacs returning to the schedule next summer, USA Swimming has opted for a different path to roster selection, opting not to hold a selection meet before the event and instead selecting the roster based upon the results of the major meets this year: US Nationals, WUGs, Worlds, US Summer Championships and Junior Worlds. This process is new to Pan-Pacs, but not unheard of, as pre-pandemic the 2015 and 2019 Worlds roster was selected the year before pulling results from the 2014 and 2018 US Nationals and Pan-Pacs.

Selecting a team a year out does have its flaws, as any of the intangibles like injury, illness or sudden improvement curves can occur in the intervening 12 months, such as the case in 2014 when Kelsi Dahlia (then Worrell) placed 6th in the 100 fly and Katie Meili placed 5th in the 100 breast. The pair were not selected to swim at the Pan-Pacs or at the 2015 Worlds, but instead swam at the 2015 Pan-Ams where they put up times that would have made them the sole U.S. representative in their respective finals, with Meili’s time of 1:06.26 theoretically finishing 2nd at the 2015 Worlds behind only the 1:05.66 Russian Yuliya Efimova posted.

Two considerations of this change to having the Pan-Pacs roster being selected the year before as compared to the World Championships rosters, is that it forces there to be a selection meet or nationals before the 2027 Worlds, which is a great pathway to establishing a routine in the lead-ip to the 2028 Olympics. It also does not force USA Swimming to select not only the World championship roster a year in advanced but also those rosters for the World University Games and Pan-Am Games.

So with that said let’s dive into the first Pan-Pacs selection procedure that does not come out of the results of just one meet. Remember, like the Worlds team, there are 26 rosters spots available for each gender but there are no limits to the number of entries per event, so if a swimmer fits into one of the priorities and is under the 26-swimmer limit, they can choose to swim any and all events at the meet.

There are two large differences from the selection procedures for the 2025 Worlds to the Pan-Pacs, the first is that with the 50s of stroke being added to the Olympic line-up and confirmed to be included in the 2026 Pan-Pacs, there selection policy has been folded into the policy regarding events other than the 100 and 200 freestyle.

The second difference is that for the 2025 Worlds there was a priority regarding the sixth fastest swimmer in the 100 and 200 freestyle, but since Pan-Pacs is not limited to two preliminary entrants per nation, the priorities have shifted to include the 3rd and 4th fastest swimmers in the non 100 and 200 freestyle events.

From the work compiled here by my colleague Sean Griffin, and taking into account the recent results from the just completed US Summer Championships the 2026 Pan- Pacs Roster sit at present as the following listed below:

On the men’s side all swimmers in Priority 1 (blue) and all swimmers in Priority 2 (red) with the exception of David Johnston. With too many swimmers in Priority 2 (2nd place finisher in events other than the 100/200 free), the tiebreaking mechanism used was finding the difference between an Available Swimmer’s Time in an Event as compared to the “A” Time Standard for that Event and then converted to a percentage. Johnston’s 1500 time of 14:56 had the lowest percentage as compared to the A-Standard.

Due to many more swimmers placing highly across events, the women’s roster got through the first three priorities before hitting their cap of 26 swimmers in the 4th priority (yellow), which is the 3rd fastest swimmer in events that are not the 100/200 free. In using the same formula as above for the men, the 27th swimmer in the list and therefore not on the team is Katie Christopherson, who hold the 3rd fastest time this season at a qualifying competition in the 200 breast.

For reference, any event with a ( * ), means that the placing is reflective of Lilly King‘s retirement while any event with a ( ^ ) means that placing is tied with another swimmer and was not resolved via a swim-off.

2016 Pan – Pacs SELECTION PRIORITIES

• Priority #1
  • Available Swimmers who have:
    • The four fastest times in the 100-meter Freestyle and 200-meter Freestyle
    • The fastest time in each event other than the 100-meter and 200-meter Freestyles
• Priority #2
  • Available Swimmers who have the second fastest time in each event other than the 100-meter and 200-meter Freestyles
• Priority #3
  • Available Swimmers who have the fifth fastest times in the 100-meter Freestyle and 200-meter Freestyle
• Priority #4
  • Available Swimmers who have the third fastest time in each event other than the 100-meter and 200-meter Freestyles
• Priority #5
  • Available Swimmers who have the fourth fastest time in each event other than the 100-meter and 200-meter Freestyles

Selection Procedure

• All Available Swimmers from Priority #1 shall be Selected to the Team.
• All Available Swimmers from Priority #2 will be Selected to the Team; provided, however,
  that if adding all Available Swimmers from Priority #2 would result in more than 26 swimmers for a gender to be Selected to the Team, then the Available Swimmers within Priority #2 shall be Selected to the Team in order of the highest Percentage of “A” Time Standard, based on the Time in the Event that qualified that Available Swimmer for Priority #2, until a maximum of 26 swimmers for that gender are Selected to the Team. This process will continue until all Priorities in Section 1.3.3. have been exhausted.
• If all Priority #2 swimmers are Selected to the Team and the maximum Team size of 26
  swimmers per gender has not been reached, then the same procedure using the highest
  Percentage of “A” Standard will be used to rank the swimmers from Priority #3 until the team
  is full.
• If all Priority #3 swimmers are Selected to the Team and the maximum Team size of 26
  swimmer per gender has not been reached, then the same procedure of using the highest
  Percentage of “A” Standard will be used to rank the swimmers from Priority #4, and Priority
  #4 swimmers will be Selected to the Team in order of highest Percentage of “A” Standard
  until the Team is full.
• If after adding Priority #4 swimmers, the Team is not full, Priority #5 swimmers will be
  Selected to the Team in order of the highest percentage of “A” Standard until the Team is
  full or until the list of Available Swimmers from Priority #1 through Priority #5 has been
  exhausted.