A right arm fast-medium bowler, Guha made her Test debut at 17 against India during their tour in 2002. As part of the same tour, Guha played in the 2002 Women's Tri-Series, and performed well, taking three wickets in England's loss against New Zealand in the final. She was the first woman of Indian heritage to play for England.
In 2002, Guha was named BBC Asian Network Sports Personality of the Year. Her best bowling in 44 One-Day Internationals is the 5 for 14 she took against the West Indies in 2008. As of 31 December 2008, she was ranked the number one bowler in the ICC Women's One Day International rankings. She took a career best 5 for 40 in her seventh Test match, against Australia at the Bradman Oval in Bowral in February 2008 and took nine wickets in the match, winning the player of the match award as England retained the Ashes. She was part of the England team which won the 2009 World Cup. She announced her retirement from international cricket on 9 March 2012, although she said she would continue to play county cricket for Berkshire.
Guha, along with Lynsey Askew, shares the world record partnership for the ninth wicket – 73 runs – in Women's ODI history.
In 2016, Guha was a member of the inaugural Triple M radio Test cricket commentary team in Australia. In 2018, she was a commentator for Sky Sports for the England/Pakistan Test matches, and was named as a commentator for Fox Cricket for their Australian cricket coverage. She was also a member of the commentary team at the 2019 Cricket World Cup. In 2020 she was the lead presenter of a new BBC TV Test and ODI highlights show.