Are there nonstop flights from Galle (KCT) to Colombo (CMB)?

Yes. Cinnamon Air fly this route. Flight time is about 40m.

Galle → Colombo

Koggala Airport (KCT) to Bandaranaike International Colombo Airport (CMB)・141 km

Nonstop flights available (1 airline). Flight time about 40m. Nonstop return flights also operate.

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