Yes, you can visit Jewel Changi during a transit, but you must physically exit the transit area (airside) and enter Singapore, which involves passing through immigration and customs. Since Jewel is located in the public "landside" area of the airport, travelers must ensure they have the necessary visa for Singapore or belong to a visa-exempt country. It is essential to complete the Singapore Arrival Card (SGAC) online before passing through immigration. Travelers are generally advised to have a layover of at least 5 hours to enjoy Jewel comfortably, as you will need to clear immigration twice (on entry and re-entry) and go through security again for your next flight. If your layover is short, you can still catch a glimpse of the Rain Vortex by taking the complimentary Skytrain that runs between Terminal 2 and Terminal 3, as its track passes directly through the Jewel complex.