While the buses are obvioulsly slower than the MRT, they have the advantage to be cheaper and to offer views of the city in contrast to the mostly underground MRT lines. Just like the the MRT lines, the buses are operated by SBS Transist or SMRT. Most bus lines stop operating at midnight (check the night buses on weekends below).
Planing your journey, Fares & Ticketing
The Public Transport website of Singapore has a fare calculator for MRT/LRT and Buses. Another great sources for planning your public transport (MRT, LRT, Bus and Taxis) within Singapore is gothere.sg
You pay with coins directly inside the buses. It is more convinient however to get to use the EZ-link card or NETS Flashpay card (for residents) or for travellers the Singapore Tourist Pass. These value cards can be uses for both MRT and Buses. When you enter the bus you tap your card to "check in" and tap again when you get off. The Singapore Tourist Pass costs S$10 per day for unlimited train and bus rides (2-Day-Pass: $16, 3-Day-Pass: $20). There is an aditional S$10 dollar deposit on the card which can be redeemed within 5 days of expiration.
The Tourist Pass can be bought at the ticket offices of theses stations: Changi Airport, Orchard, Chinatown, City Hall, Raffles Places, Ang Mo Kio, HarbourFront, Bugis.
NightRider (SMRT) / Night Owl (SBS Transit) Buses
These night buses runs Fridays, Saturdays & eve of Public Holidays from midnight to 2am from the city center (Marina Center and nightlife districts at Boat Quay, Clarke Quay, Mohamed Sultan and Orchard). The buses run every 20-30 minutes, the fare is S$4.50.
Click on the links below for more information and route maps:
NightRider (operates from 11.30pm - 4.30am)
NightOwl (operatores from midnight - 2am)