Are there nonstop flights from Singapore (SIN) to Jeju City (CJU)?

Yes. Scoot, Trinity Airways fly this route. Flight time is about 5h 32m.

What is the fastest connection from Singapore (SIN) to Jeju City (CJU)?

via Wenzhou ≈ 6h 2m, via Taipei ≈ 6h 2m, via Ningbo ≈ 6h 3m (estimated flying time, excluding layovers).

from 18,500 ANA miles, from 23,000 JAL miles (economy, one way, based on the published award charts).

Singapore Changi Airport (SIN) to Jeju International Airport (CJU)・4,276 km

Nonstop flights available (2 airlines). Flight time about 5h 32m. Nonstop return flights also operate.

With milesANA 18,500 miles+ (via SZX)JAL 23,000 miles+ (via PVG)Economy, one way, estimate. Tap a connection for miles by cabin.

24 one-stop options, sorted by estimated flying time. Tap one to see the airlines on each leg and booking links.

Times are estimated from distance. Check schedules, frequency and availability with the airline or a booking site.