Brookes made her county debut in 2005, for Worcestershire against Warwickshire.[3] Brookes began to play regularly for Worcestershire in the 2009 season, and hit 224 runs in the County Championship that season, at an average of 37.33.[4] In 2011, she was the seventh-highest run-scorer across the whole County Championship, with 363 runs at an average of 51.85, as well as hitting 141 runs, the most for Worcestershire, in the Twenty20 Cup.[5][6] In 2013, Brookes hit her maiden county century, scoring 110* against Wales, as well as taking her List A best bowling figures, of 4/26 against Somerset.[7][8] She was also the joint-second leading wicket-taker across the whole County Championship that season, with 18 wickets.[9] In 2015 and 2016, Brookes was successful in the Twenty20 Cup, scoring 260 (third highest overall) and 270 (second highest) runs, respectively.[10][11] She also hit her List A high score in 2016, with 128 against Leicestershire.[12]
In 2018, Brookes joined Warwickshire, hitting 168 runs at an average of 33.60 in the County Championship that season.[13] In 2019, she helped her side to the title in the Twenty20 Cup, scoring 157 runs at an average of 31.40.[14][15] She was the side's second-highest run-scorer in the 2022 Women's Twenty20 Cup, with 147 runs including one half-century, as well as taking four wickets.[16][17] She joined Surrey for the 2023 Women's Twenty20 Cup, taking three wickets in the competition.[18][19]
Brookes also played in the Women's Cricket Super League in all four seasons. In 2016, she played for Loughborough Lightning, helping them reach the semi-final and scoring 43 runs.[20] She continued playing for the side in 2017, and hit 48 runs in 5 innings that season.[21] In 2018, she moved to Yorkshire Diamonds, hitting her WCSL high score of 45* against Southern Vipers and taking 3 wickets.[1][22] Brookes joined Southern Vipers for the 2019 season, playing 7 matches and scoring 43 runs.[23]
In 2020, Brookes played for Central Sparks in the Rachael Heyhoe Flint Trophy. She appeared in three matches, scoring 10 runs and taking 2 wickets at an average of 21.50.[24][25] In 2021, Brookes played ten matches for the side across the Rachael Heyhoe Flint Trophy and the Charlotte Edwards Cup, with a top score of 33 in her side's Rachael Heyhoe Flint Trophy victory over South East Stars.[26][27][28] She was also in the Birmingham Phoenix squad for The Hundred, but did not play a match and was not retained for the 2022 season.[29] She played five matches for Central Sparks in 2022, across the Charlotte Edwards Cup and the Rachael Heyhoe Flint Trophy.[30][31] Ahead of the 2023 season, it was confirmed that Brookes had left Central Sparks.[32]
Brookes also appeared in the Super Fours in 2011 and 2012, for Diamonds.[33]