 Tan became an MP for the first time after the 2006 general election, when Tan's five man team, representing the People's Action Party, defeated the Workers' Party of Singapore with 63.86% of the votes for East Coast GRC.The votes in the 2011 general election narrowed to 54.8% for the PAP.In the 2015 Singaporean general election, she returned to Parliament after her team defeated the Worker's Party with 60.7% of the popular vote, an increase of 5.9%.