Peat began playing basketball at 13. Peat's mother, Marian, encouraged her to join a local basketball team in order to keep her occupied during the school summer holidays.[4][8] Between 2005 and 2015 Peat played as a point guard for DCU Mercy, helping them win the 2007 and 2011 Basketball Ireland Women's Superleague titles.[12][13][14][15] She also captained DCU Mercy to two National Cup wins in 2010 and 2011 [5][16] and represented the team at intervarsity level.[17] In addition to playing for DCU Mercy, Peat has also served the club in various other capacities including club captain, coach, administrator and chairperson.[18]
Within months of taking up women's rugby union, Peat was fast-tracked into the Ireland team by Tom Tierney. On 14 November 2015 she made her international debut when she came on as a replacement in an 8–3 defeat against England in an Autumn International at Twickenham Stoop. This was only Peat's eighth ever rugby union match.[2][5][11][42][43]
She is a vocal advocate for gay rights and was an ambassador for the 2019 Union Cup when she revealed that she only came out to her family and friends when she was 30.[46]
In 2020, the Irish Examiner newspaper named her ninth in the Top 10 Most Influential Women in Irish sport.[47]