By MRT:

Promenade MRT Station (CC4 / DT15)
Walk through Millenia Walk to reach Marina Square.
Exit from Millenia Walk’s entrance facing Raffles Boulevard and get on the escalator to Level 2.

Esplanade MRT Station (CC3)
Enter Marina Square via Marina Link which is located at Exit B of Esplanade MRT Station.

City Hall MRT Station (NS25 / EW13)
Walk through CityLink Mall to reach Marina Square.
Turn right and get on the escalator once you see directional signage indicating Marina Square.

By Bus:

Temasek Boulevard (Suntec Convention) Bus stop
Buses you can take:
36, 36B, 70A, 70M, 97, 97E, 106, 111, 133, 162M, 502, 502A, 518, 518A, 531, 700A, 857, 868

Esplanade Drive Bus stop (Near One Raffles Link)
Buses you can take:
10, 57, 70, 128, 162, 196, 531, 700, 850E, 868, 971E, N2, NR5, NR7, NR8

Raffles Boulevard (Pan Pacific Singapore) Bus stop
Buses you can take:
36, 36A, 36B, 56, 75, 77, 97, 97E, 106, 107M, 171, 195, 700A, 857, 960, 961C, NR2, NR5, NR7, NR8

Raffles Avenue (Esplanade Theatre) Bus stop
Buses you can take:
IN, 2N, 3N, 4N, 5N, 6N, 36, 36A, 36B, 56, 70M, 75, 77, 97, 97E, 106, 111, 133, 162M, 171, 195, 195A, 531, 700A, 857, 960, 961C, NR1, NR2, NRS, NR6, NR7, NR8