Night Safari (night zoo in the open - a world's first). The Night Safari is located next to the Singapore Zoological Gardens (Zoo) in Mandai. It would be wise to allocate a day to see all, at these two places. The Singapore Zoo opens from 8.30am-6.00pm while the Night Safari operates from 7.30pm - 12.00am (last admission at 11.00pm). You can skip the tram ride at the Zoo (all exhibits can be reached by foot) but might want to pay extra (SGD 6) for the tram ride at the Night Safari as some parts of the Safari are only open to the trams. Travel by MRT to Ang Mo Kio Station and hop on Bus Service 138 from the bus interchange. The bus takes you all the way to the Zoo/ Safari. Alternatively, you might want to take a cab from town - this would cost about SGD 15 (more/less).
Jurong Birdpark is one of the world's largest walk-in aviary with the tallest man-made waterfall. Opening hours, for this attraction located at Jurong, is from 9.00am-6.00pm. To get there, take the MRT to Boon Lay Station and hop on Bus Service 194 or 251 at the bus interchange.
Botanical Garden (don't miss the Orchid section)
Little India (check out the hindu temples)
Chinatown (walk the small back alleys and see interesting old professions that still exist)
Marina South (Suntec City and kite flying) Kite-flying, buffet steamboats at Marina South Take the MRT to Marina Bay, take bus, taxi or walk (will be a long one). For shopping, Suntec City is one of the bigger malls in Singapore. There's also Marina Square Shopping Centre and Millenia Walk Mall in the same vicinity
Orchard Road (all the skyscrapers with fancy shopping centres)
Raffles Hotel (check out the Long Bar, with peanut shells on the floor - the only place in Singapore where you won't be fined for throwing food on the floor - and home of the world-famous Singapore Sling)
St. Andrews Cathedral
take the MRT on a loop for a joyride to see how Singaporeans live in all those colorful highrise apartments.This is the routine I do everytime I go home to visit.
Of course don't forget all the yummy makan (food) at the hawker centers and food courts.
Oh, and there is Sentosa, which is rather touristy, but it is still something different to see. At Sentosa, you should go on the Carlsberg Tower, I heard it provides a breathtaking 360-degree view of Singapore and some of the neighbouring islands.
Boat Quay and Clarke Quay are tourist traps with Clarke Quay being the more expensive place to go, but Boay Quay is pretty laid back, with more pubs and a view to rival Circular Quay, Sydney. You could take a walk to One Fullerton and marvel at the Merlion Statue with the majestic Fullerton Hotel and city skyscrapers as the backdrop. Across the harbour, you can see the towering Esplanade, home to the performing arts.