Are there nonstop flights from Singapore (SIN) to Porto (OPO)?

No. The fastest connection is via Istanbul, about 14h 52m of total flying time.

What is the fastest connection from Singapore (SIN) to Porto (OPO)?

via Istanbul ≈ 14h 52m, via Barcelona ≈ 14h 52m, via Rome ≈ 14h 53m (estimated flying time, excluding layovers).

from 29,500 ANA miles, from 45,000 JAL miles (economy, one way, based on the published award charts).

Singapore Changi Airport (SIN) to Francisco de Sá Carneiro Airport (OPO)・11,777 km

No nonstop flights. The fastest connection is via Istanbul (IST), about 14h 52m of flying time (layover not included).

With milesANA 29,500 miles+ (via IST)JAL 45,000 miles+ (via CDG)Economy, one way, estimate. Tap a connection for miles by cabin.

None.

19 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.