No, you cannot visit the main areas of Jewel Changi Airport once you have cleared departure immigration, as Jewel is located on the landside (public side) of the airport. If you are a departing passenger, you must visit Jewel before you go through passport control. If you are a transiting passenger and wish to see Jewel's shops or the waterfall up close, you must actually clear arrival immigration to enter Singapore (which may require a visa depending on your nationality). However, there is a "transit hack" for 2026 travelers: you can catch a glimpse of the waterfall for free without leaving the transit area by taking the Skytrain that runs between Terminal 2 and Terminal 3, as the tracks pass directly through the heart of the Jewel complex. Just be sure you have enough time to return to your departure gate, as clearing immigration twice can be time-consuming.