Outram Park MRT Station was created in 1987.
Farrer Park MRT Station was created in 2003.
You could hire a taxi (the more expensive but more comfortable option). You could also take the train from Changi Airport till Outram Park MRT station. Then change trains to the Purple line and take it from Outram Park all the way to Harbourfront MRT station. (take note: you will have to walk quite a bit to change trains, but is a covered link)
Kembangan MRT Station was created in 1989.
Kovan MRT Station was created in 2003.
Bartley MRT Station was created in 2009.
Esplanade MRT Station was created in 2010.
MacPherson MRT Station was created in 2010.
Boni MRT Station was created in 1999.
Novena MRT Station was created in 1987.
Expo MRT Station was created in 2001.
Commonwealth MRT Station was created in 1988.
Marsiling MRT Station was created in 1996.