Yes, you can visit Jewel Changi after checking in, but it is a "High-Fidelity" necessity to understand that Jewel is located in the landside (public) area of the airport. To visit after checking in, you must use an "Early Check-In" service, which is available for many airlines (including Singapore Airlines and Emirates) between 3 and 24 hours before your flight. After dropping your bags and receiving your high-fidelity boarding pass at the Jewel Early Check-In Lounge on Level 1, you are free to explore the Rain Vortex and Shiseido Forest Valley with just your carry-on luggage. However, once you pass through Immigration and Passport Control to enter the "Airside" departure gates, you cannot return to Jewel without "High-Fidelity" re-entering Singapore (which requires another immigration clearance). For 2026 travelers, it is a high-fidelity rule to allow at least 90 minutes to get from Jewel back through immigration and to your specific terminal's departure gate before your flight departs.