Along with teammates Matt Grevers, Lilly King, and Simone Manuel, the American team won gold in a new world-record time of 3:38.56. That time broke the record set earlier in the day by Ryan Murphy, Kevin Cordes, Kelsi Worrell, and Mallory Comerford. On day five, Dressel re-set the 100-meter freestyle American record with a 47.17 in the 100 meter freestyle final, en route to winning gold by a margin of 0.70 seconds over silver medalist and teammate Nathan Adrian. On day seven, Dressel became the first swimmer ever to win three gold medals on a single day. He won the 50 meter freestyle in 21.15, a new world textile best time. Half an hour later he won the 100 meter butterfly in 49.86, again a new world textile best and 0.04 seconds above the world record held by Michael Phelps. The third gold medal came in the 4×100 meter mixed freestyle relay, where he led off in 47.22. Dressel and teammates Adrian, Comerford, and Manuel broke the world record for this relay with a time of 3:19.60. On the eighth and last day of competition, Dressel won his 7th gold in the 4×100-meter medley relay. Swimming the butterfly leg, Dressel recorded a time of 49.76 and the American team of Matt Grevers, Kevin Cordes, and Nathan Adrian won with a time of 3:27.91. At the 2018 NCAA Division I Men's Swimming and Diving Championships, Dressel won all three of his individual races, and won his first relay national title. On day 2 of the competition, March 22, 2018, Dressel broke the American and US Open records in the 50 yard freestyle thrice. He first swam an 18.11 in the individual preliminaries race in the morning session. He later improved upon that record in the evening leading off The University of Florida's national championship winning relay with a 17.81 split, and finalized his record with a 17.63 in the 50 yard freestyle final. The next day, he broke the American and US open records in the 100 yard butterfly, swimming a 42.80. On the final day of competition, Dressel won the 100 yard freestyle by more than a second in a time of 39.90, completing his sweep of individual events for a second time. This secured him CSCAA Swimmer of the Meet honors for the third year in a row, as he became the first swimmer ever to break the 18 second 50 free barrier, the 40 second 100 free barrier, and the 43 second 100 fly barrier in the history of yards swimming.