Are there nonstop flights from Singapore (SIN) to Changsha (CSX)?

Yes. China Southern Airlines, Xiamen Airlines, Scoot fly this route. Flight time is about 4h 12m.

What is the fastest connection from Singapore (SIN) to Changsha (CSX)?

via Sanya ≈ 4h 41m, via Ho Chi Minh City ≈ 4h 42m, via Haikou ≈ 4h 42m (estimated flying time, excluding layovers).

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

Singapore Changi Airport (SIN) to Changsha Huanghua International Airport (CSX)・3,141 km

Nonstop flights available (3 airlines). Flight time about 4h 12m. Nonstop return flights also operate.

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

41 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.