Are there nonstop flights from Chicago (MDW) to Porto (OPO)?

No. The fastest connection is via Boston, about 8h 33m of total flying time.

What is the fastest connection from Chicago (MDW) to Porto (OPO)?

via Boston ≈ 8h 33m, via Newark ≈ 8h 39m (estimated flying time, excluding layovers).

Chicago Midway International Airport (MDW) to Francisco de Sá Carneiro Airport (OPO)・6,331 km

No nonstop flights. The fastest connection is via Boston (BOS), about 8h 33m of flying time (layover not included).

None.

2 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.