The Aggies finished first in NCAA Division II six times in 2003 and won the NACDA Director's Cup four years in a row from 1999 to 2003.

Following a year of heavy discussion by campus administrators, faculty, staff, students, alumni and the local community, taking a cue from the advisory vote, UCD chancellor Larry Vanderhoef officially announced the university's move to Division I on March 11, 2003.

Following a successful stint as an NCAA Division II program, the UC Davis women's basketball team began its transition to the NCAA Division I level in 2003–04, officially competing as a member of the Big West Conference in 2007–08.The team plays its home games at a 7,600-seat arena called University Credit Union Center.

[15] The UC Davis Aggies men's water polo team has won seven WWPA title, including back-to-back championships in 2021 and 2022.

UC Davis sprinter Matthew Okonkwo captured a share of the Big West Conference Male Track Athlete of the Year in 2022.

Okonkwo captured Big West individual titles in each of the 200- and 400-meter dashes at the championship meet, while helping both relay squads to top-three finishes.

School Records UC Davis men's golf has tallied 41 team wins and 53 individual victories dating back to 1993.

School Records UC Davis captured its first Big West Championship in 2010 when individual conference champion Jonathan Peterson led the Aggies to their historic victory.

Records UC Davis added beach volleyball ahead of the 2019 season, joining Equestrian as the department's newest sports.

In less than half a decade, UC Davis women's track & field boasted three finalists – including two winners – for the NCAA Woman of the Year Award, which honors excellence and leadership in athletics, academics and in the community.

Since then, UC Davis is the only Division II institution to have won the award and is one of just two schools to have three winners (Aggie lacrosse player Kelly Albin captured the honor in 2004).

Records UC Davis added Equestrian ahead of the 2019 season and the program instantly enjoyed success, earning their first ECAC Championship in 2023.

UC Davis women's golf is led by the three-time Big West Golfer of the Year and former LPGA Tour professional Demi Runas.

The Aggies have posted 23 team wins as well as 22 individual victories since the program started in 2005, also making four NCAA Tournament appearances (2008, 2011, 2013, 2015) over that time.

Led by Cal Aggie Athletics Hall of Fame student-athlete Tanya Ho, UC Davis gymnastics earned their first conference title since 2015 after a brilliant 2023 campaign.

Records In March, 2020, UC Davis women's tennis also earned an NCAA Public Recognition Award for an outstanding Academic Progress Rate (APR) by posting its 12th perfect score in program history.

As a Division II team, UC Davis captured the California Collegiate Athletic Association title three times in a row from 1999 to 2002.

Led by three-time Mountain Pacific Sports Federation (MPSF) Coach of the Year (2018, 2019, 2021), Suzanne Isidor captured her first conference title in 2021, leading the Aggies to a program-best 12–4 record.

UC Davis women's volleyball ascended to the Division I level ahead of the 2004 season and have not won a conference title since the reclassification.

UC Davis Softball ascended to the Division I level in 2008 and claimed their first Big West Conference title in 2010 under Head Coach Karen Yoder.

UC Davis women's water polo earned a share of the Big West Conference title in 2009, their first championship in program history at the Division I level.

[25] The Aggies also pulled off an upset against Stanford in basketball just months later, beating the Cardinal 64–58 with a late rally at home on December 4, 2005.

The UC Davis Aggies won the men's 2015 DI-AA college rugby championship by defeating Central Florida in the final 18–15 at Kennesaw State University's Fifth Third Bank Stadium.

[30] The men repeated as the 2016 D1-AA as national champions by defeating the Notre Dame College of South Euclid, Ohio, in the final by a score of 17–13.