[4] She made her first major impression on the league in her third appearance by taking a difficult match-winning catch on the last ball of a three-run victory against the Melbourne Renegades at Blacktown ISP Oval.
Primarily contributing to the team through her medium-pace bowling, Darlington claimed 16 wickets during the tournament at an economy rate of 6.82, leading to her winning the WBBL|05 Young Gun Award and being named the Thunder's Player of the Season.
[11][12] After overcoming a lower-leg injury early in the 2020–21 season, Darlington affirmed her status as "one of the best death bowlers"[13] in the league—on 8 November at Hurstville Oval, for example, she restricted the Hobart Hurricanes to nine runs off the final over of the match to help secure a one-run victory.
[17] Having missed out on a WNCL contract for the 2019–20 season, Darlington opted to spend much of the summer overseas playing for the Otago Sparks in New Zealand's domestic T20 competition, the Women's Super Smash.
[19][20] Darlington made her debut for the New South Wales Breakers during the 2019–20 Women's National Cricket League season, taking 2/29 from ten overs in a one-wicket victory against Tasmania.