Sentosa is an island resort in Singapore. There are a number of hotels on Sentosa island, including the Hard Rock Hotel and W (part of Starwood). We would recommend either the Capella or TreeTop Lofts. We tend to stay on the mainland and just visit for a day.
The island is fine for an easy day out if you are jet-lagged, but we wouldn't class it as a must-see in Singapore (unlike the excellent orchid garden, which is worth the 13 hour flight from Europe on its own). Having said that, the amusement park makes it a good place if you are travelling with children. 70% of the island is covered by rainforest, so you have the chance of seeing monitor lizards, monkeys, peacocks and parrots. The island also has a perfect white beach, but most people visit for the various attractions on offer. We would suggest checking Groupon for offers as these can offer great value for money.
Although you can reach the island by road (a bus runs from the city) or monorail, we prefer to use the cable car (shown above). Once on the island, there is an observation tower, oceanarium complete with dolphin park, 4D theatre and the ubiquitous Madame Tussauds.
If you are seeking something more active, iFly offers the world's largest vertical wind tunnel, allowing you to experience sky diving without the danger! Also fun is the Skyline Luge toboggan that you drive down a hill and the MegaZip Adventure Park complete with zip-wires and aerial adventures.
Built in the 1880s, Fort Siloso has the only surviving coastal gun battery from the Second World War. Ammunition bunkers, barracks, tunnels and gun emplacements are open to visitors interested in modern history.