The 18-year-old Havant and Hampshire all-rounder joins England trio Tammy Beaumont, Danny Wyatt and Tash Farrant in renewing their contracts with the Ageas Bowl outfit.
Suzie Bates also returns, however, Beaumont will take over from the New Zealand star as skipper.
The Vipers, who won the inaugural title in 2016 and reached Finals Day the following summer, have announced two new overseas signings.
West Indies superstar Stafanie Taylor and Australia all-rounder Sophie Molineux have signed up.
Denver Hume: Portsmouth's expensive forgotten man and why former Sunderland defender really could be one for the future
'Real driving force... lion-hearted display... classy presence' - Neil Allen's Portsmouth ratings from 3-0 Carabao Cup win at Cardiff
Cardiff 0 Portsmouth 3: Neil Allen's verdict - From Fratton boos to 'Just like watching Brazil' as brilliant Blues produce remarkable cup shock
'We’ve got a real problem': Portsmouth boss reveals headache after career first at Cardiff
Portsmouth transfer news: The four Fratton Park departures Blues could still sanction before window shuts - including ex-Sheffield United defender and Luton midfielder
Charlotte Edwards the Ageas Bowl director of women’s cricket, said: ‘Sophie is one of the most exciting young players in the world.
‘She has dominated the WBBL and won the World T20 with Australia – and she’s still only 21.
‘Stafanie is the number one all-rounder in world cricket and her record speaks for itself.
‘We are very lucky to have secured their signings for this year’s Kia Super League.’
Other new additions include Marie Kelly, Thea Brookes and fast bowler Issy Wong, who were all part of the Birmingham Bears’ victorious T20 side earlier this season.
Maia Bouchier, Lauren Bell, Carla Rudd, Paige Scholfield and Fi Morris complete the squad.
The Vipers, who disappointed last summer, begin their group fixtures with a trip to Liverpool to play Lancashire Thunder on Sunday, August 6.
Western Storm visit the Ageas Bowl on Sunday, August 11.
All six teams will play each other home and away before the top three qualify for Finals Day at Hove on Sunday, September 1.