The BBC's Cindy Sui profiles the three choices on the voting slip.
Ms Tsai from the opposition Democratic Progressive Party (DPP) is the party's chairwoman, a former vice premier, and was Taiwan's first female presidential candidate during the 2012 presidential race in which she lost to Ma, but managed to get 45% of the votes.
She once served as Minister of the Mainland Affairs Council and was one of the chief drafters of the "special state-to-state relations" doctrine of then President Lee Teng-hui, which defined Taiwan and China's relationship on country-to-country terms, angering Beijing and leading to heightened tensions.
She has since moderated her views, promised to maintain peaceful and stable relations and expressed her openness to having talks with Chinese officials.
But she has refused to accept Beijing's precondition that she first accept that Taiwan is a part of "one China."
Mr Chu is the mayor of Taiwan's most populous city, New Taipei City, and is chairman of the ruling Kuomintang party (KMT) as well as a former vice premier.
He is believed to be the party's best chance at defeating Tsai, but came into the race late after the KMT replaced a female candidate with him, at the last stretch.
Like Ma, he favours building stronger economic ties with China, seeing that as crucial to lifting Taiwan's economy out of the doldrums and preventing economic isolation.
Just as in 2012, Mr Soong from the smaller People First Party is running because he says Taiwanese people should have a third choice.
Once a KMT member, he has shunned concerns that his candidacy may cause the KMT to lose votes and end up helping the DPP.
Taiwan will see its new president take power later this month after the 16 January election, as incumbent Ma Ying-jeou finishes his second and final term.