At the official Women's Big Bash League (WBBL) launch on 10 July 2015, Duffin was unveiled as the first-ever player signing for the Perth Scorchers.
However, beginning in November 2015, Duffin stepped away from her domestic cricket commitments which would lead to missing the whole inaugural WBBL season.

In June 2016, a month after Duffin signalled a return to top-level domestic cricket, the Melbourne Stars announced they had "won the race for the prized signature of the former Australian batter" by recruiting her for the WBBL|02 season.

On 20 January 2017, in a match against the Hobart Hurricanes at Bellerive Oval, Duffin pulled off arguably the most unlikely victory of her career.
Facing Amy Satterthwaite and needing 12 runs from the last two legal deliveries, Duffin hit a six off the first ball.
Then, she hit a four off what was deemed a no-ball.
With Satterthwaite having to bowl an additional delivery, Duffin worked a single through the leg side to claim a last-gasp six-wicket win.

In September 2017, Duffin switched to the Stars' crosstown rival, signing with the Melbourne Renegades ahead of WBBL|03.
In the first game of the season, on 9 December 2017 against the Sydney Thunder at North Sydney Oval, she recorded her highest WBBL score with an innings of 81 off 47 and was named Player of the Match.
Requiring 28 more runs with 17 balls remaining, Duffin was dismissed in controversial fashion by what commentators and players believed to be an illegitimate catch.
The momentum of the contest then swung dramatically and the Renegades lost by eleven runs.

In September 2019, the Renegades announced Duffin as the team's captain for WBBL|05, replacing Amy Satterthwaite who would sit out 2019–20 due to pregnancy.
Coincidentally, Duffin would miss one game during the season, the cause of which was later revealed to be a case of morning sickness.
Nevertheless, she had a stellar tournament, scoring 544 runs at 68.00 with a strike rate of 138.77.
Among her highlights was an unbeaten 27-ball innings of 50 runs on 27 November 2019 against the Brisbane Heat, helping the Renegades mow down a target of 184 and set a new league record for the highest successful chase.
Although the Renegades would be eliminated in the semi-finals for the second-straight year, Duffin received individual acclaim by being named captain for the Team of the Tournament.
At the official Women's Big Bash League (WBBL) launch on 10 July 2015, Duffin was unveiled as the first-ever player signing for the Perth Scorchers. However, beginning in November 2015, Duffin stepped away from her domestic cricket commitments which would lead to missing the whole inaugural WBBL season.
In June 2016, a month after Duffin signalled a return to top-level domestic cricket, the Melbourne Stars announced they had "won the race for the prized signature of the former Australian batter" by recruiting her for the WBBL|02 season.
On 20 January 2017, in a match against the Hobart Hurricanes at Bellerive Oval, Duffin pulled off arguably the most unlikely victory of her career. Facing Amy Satterthwaite and needing 12 runs from the last two legal deliveries, Duffin hit a six off the first ball. Then, she hit a four off what was deemed a no-ball. With Satterthwaite having to bowl an additional delivery, Duffin worked a single through the leg side to claim a last-gasp six-wicket win.
In September 2017, Duffin switched to the Stars' crosstown rival, signing with the Melbourne Renegades ahead of WBBL|03. In the first game of the season, on 9 December 2017 against the Sydney Thunder at North Sydney Oval, she recorded her highest WBBL score with an innings of 81 off 47 and was named Player of the Match. Requiring 28 more runs with 17 balls remaining, Duffin was dismissed in controversial fashion by what commentators and players believed to be an illegitimate catch. The momentum of the contest then swung dramatically and the Renegades lost by eleven runs.
In September 2019, the Renegades announced Duffin as the team's captain for WBBL|05, replacing Amy Satterthwaite who would sit out 2019–20 due to pregnancy. Coincidentally, Duffin would miss one game during the season, the cause of which was later revealed to be a case of morning sickness. Nevertheless, she had a stellar tournament, scoring 544 runs at 68.00 with a strike rate of 138.77. Among her highlights was an unbeaten 27-ball innings of 50 runs on 27 November 2019 against the Brisbane Heat, helping the Renegades mow down a target of 184 and set a new league record for the highest successful chase. Although the Renegades would be eliminated in the semi-finals for the second-straight year, Duffin received individual acclaim by being named captain for the Team of the Tournament.
Jess Duffin