Briggs played for Waterford at senior inter-county level. In 2005 she played in the Munster Senior Championship final against Cork at Páirc Uí Rinn.[9] On 9 July 2009 Briggs scored 2–3, including a 30-metre point, as she helped Waterford defeat Clare 2–14 to 2–10 as they won the Munster Intermediate Championship final.[11] In 2010 she played for Waterford in two further Intermediate finals. On 3 July she played in the Munster Intermediate Championship final as Waterford defeated Limerick.[12][13] On 26 September she also played for Waterford in the 2010 All-Ireland Intermediate Ladies' Football Championship final. Waterford played a Donegal team that included Briggs' Ireland women's rugby union international teammate, Nora Stapleton.[14][15][16][17][18]
Briggs has played for Munster in the IRFU Women's Interprovincial Series.[18] She was recruited by Munster in 2007 after being spotted playing tag rugby by then Munster U21 manager, Kate McCarthy.[20] She was subsequently a prominent member of the Munster teams that won the Interpro title in the 2007, 2008, 2009, 2010 and 2012.[12][19][21][22] In 2015 she was named captain of the Munster team.[23]
During the 2009 Women's Six Nations Championship, Briggs was a member first Ireland team to defeat France.[26] In 2013 Briggs was a prominent member of the Ireland team that won their first ever Six Nations, Grand Slam and Triple Crown titles. Briggs scored three tries and kicked 28 points and finished the championship as the top points scorer with 43. This included a try, a conversion and a penalty as Ireland defeated England 25–0 on 9 February. This was Ireland's first ever win against England. Ireland secured the Grand Slam and with a 6–3 away win against Italy on Saint Patrick's Day. Two penalties from Briggs gave Ireland their fifth win in a row.[27][19][18][28][29][30] Briggs was subsequently named the Guinness Rugby Writers of Ireland Women's Player of the Year for 2013.[19][31]
Briggs was later named the Ireland Women's Player of the Year for a second successive year.[36] Briggs captained the Ireland team that won the 2015 Women's Six Nations Championship and again finished the championship as the top points scorer, this time with 49.[12][24][37][38][39]