Chiang Rai Airport (IATA: CEI) has multiple daily flights from Bangkok's Suvarnabhumi and Don Mueang airports, taking around 1.5 hours. Thai Airways, Bangkok Airways, and budget carriers all serve the route. Flights from Chiang Mai also operate, though the bus is often more practical for that short hop.
By bus, Chiang Rai is about 3 hours from Chiang Mai on comfortable air-conditioned coaches that depart from Chiang Mai's Arcade Bus Terminal. Minivans are faster and run more frequently; they depart from various points around Chiang Mai and drop you in Chiang Rai town centre. From Bangkok by bus is around 10 hours overnight. The bus terminal in Chiang Rai is a short tuk-tuk ride from the city centre.