Sarah Megan Law caught the rugby bug aged six when her referee dad, Andy, who was then playing for Penicuik, took her to the club's mini section. She played in the mixed mini side throughout her primary school years before moving on to Wanderers' girls, age 12, where she played in the under-15 team.

She played in numerous schools' cup finals and, in 2012, scored 32 points and picked up Player of the Match as Wanderers beat Plockton HS to the Brewin Dolphin Scottish Schools Shield.

She began playing for Wanderers' senior team in January 2012, as she had just turned 17, and helped them win the league and cup double that season.

Having already played for Scotland at under-20 level, she successfully trialled for Scotland Women 7s in 2012 and, after playing for the Wooden Spoon 7s (alongside Irish, Scottish and Spanish internationalists) in Kinsale, she represented her country at Rugby Rocks London and the FIRA WRWC qualifier in Moscow, continuing to play in the two FIRA Grand Prix events in 2013. She has continued to turn out for Scotland 7s each season since.

She made her senior Scotland debut off the bench in Esher against England in the Women's Six Nations opener in February 2013 and scored her first points, a conversion, against Sweden in the eleven-try FIRA victory in Madrid in April 2013.

Law held her nerve to seal Scotland Women's 15-14 win against Wales in the 2017 Six Nations as she successfully kicked a penalty in the dying minutes of the match at Broadwood Stadium.

A former pupil of Penicuik HS where she was Head Girl, Sarah graduated with a BSc (Hons) in Applied Maths from the Edinburgh University before undertaking a part time Masters in Operational Research with Data Science.

In 2019 Sarah signed for Darlington Mowden Park.