Howarth started playing soccer in 1999 for the Flint Steelers. She played for the team until 2005 and then joined the Michigan Hawks youth team until 2009.[2]
University of Miami
In 2009, she started playing collegiate soccer for the Miami Hurricanes for which she played until 2012.[2] While playing for the Hurricanes, Howarth was named Second-Team All-ACC and the NCAA Division I All-Southeast Third Team in 2011.[2][3]
In March 2013, Howarth reported to the Portland Thorns for preseason. After the signing deadline, Howarth's rights were released and she was put on waiver. Boston Breakers immediately obtained Howarth's rights.[citation needed]
In April 2013, Howarth signed a professional contract with the Boston Breakers of the National Women's Soccer League after training with the team.[4] She made her professional debut for the team on May 4, 2013, in a match against the Chicago Red Stars in which she came on as an 89th-minute substitute for Sydney Leroux. Boston won the match 4–1.[5] After making four appearances for the Breakers, she was waived by the team in June 2013.[6]
New England Mutiny, 2014–2019
After a season with the Boston Breakers, Howarth returned to the Mutiny to captain the team.[citation needed] She was named to the all-UWS first team in 2016–2019.[citation needed] In 2019, Howarth was also named Player of the Year, where she scored in every game she appeared in.[7]
Howarth is Mutiny's all-time leading goalscorer and point-scorer with 69 and 155 respectively.[8]