Seoul or Taipei, or Bangkok
A connection through Seoul or Taipei can keep the long-haul journey outside Thailand until the final flight into CNX. In that setup, Thai immigration waits for you in Chiang Mai. Connect in Bangkok and continue on a domestic flight, and immigration happens in Bangkok before the Chiang Mai leg.
That distinction matters more than the map suggests. A through ticket keeps the connection inside the airline’s responsibility. Separate tickets put missed-connection risk, baggage timing, and re-checking onto you.
I would keep the long-haul and Chiang Mai leg on one ticket where possible. If separate tickets are unavoidable, I would choose the connection city with enough slack to absorb immigration and baggage without turning the trip into an airport sprint.
Bangkok airport codes are not interchangeable
Bangkok uses Suvarnabhumi, code BKK, for much of its international traffic. Don Mueang, code DMK, handles a large low-cost operation. Flights to Chiang Mai leave from BKK and DMK.
Thai Airways and Bangkok Airways serve CNX from BKK. Nok Air uses DMK. Thai AirAsia flies from both. The airline name by itself does not tell you which Bangkok airport the connection needs. The code does.
This is where an attractive combination can become silly. A long-haul flight can land at BKK while the onward Chiang Mai booking leaves from DMK. Suvarnabhumi sits east of the city; Don Mueang sits to the north. Getting between them means crossing Bangkok traffic with your luggage.
Airports of Thailand runs a free shuttle between BKK and DMK, but it is for connecting passengers. Staff ask for the boarding pass of the onward flight and a passport or ID. A traveler assembling separate bookings without an onward boarding pass may not qualify.
If the long-haul lands at BKK, I would look for the Chiang Mai leg from BKK before entertaining a transfer to DMK. Bangkok traffic has not seen your carefully optimized booking and feels no obligation to help.
Do the Thailand paperwork on the official sites
US passport holders can visit Thailand without a visa for tourism, for stays of up to 30 days. If the trip goes beyond the exemption, the official Thai e-Visa site is thaievisa.go.th.
Foreign visitors also complete the Thailand Digital Arrival Card before entry. Use tdac.immigration.go.th. The form is free, generates a confirmation or QR code, and each traveler needs their own submission, including children. It is not a visa.
Type the address yourself instead of clicking an ad. Lookalike sites charge for the same form, which is a remarkably efficient business model if your product is somebody else’s free government page.
I would do the TDAC before the airport day and keep the confirmation available offline.
CNX puts you close to the Old City
Chiang Mai International Airport sits southwest of the Old City, the square historic core ringed by a moat with stretches of brick wall and gates. Unlike the Bangkok connection problem, the final ground transfer is straightforward.
An official airport taxi counter sits outside arrivals. Grab and Bolt also work at CNX, with app pickups using a marked point outside rather than the taxi rank. The city’s red shared trucks, called songthaew and locally rot daeng, carry passengers into town as well.
There is no airport train. The airport is close enough to the city that road transport does the job.
I would use the official taxi counter or an app when arriving with luggage and a specific hotel address. Save the red trucks for when the shared-ride format actually suits the trip rather than using them because a guidebook says they are local.
The season can matter more than the hotel deal
Chiang Mai’s cool season runs roughly from November through February, bringing dry, warm conditions by day and cooler evenings. Pack a layer if you are heading into the hills.
Late in the dry season, smoke from burning in fields and hills can settle over Chiang Mai’s basin. The haze often builds from late February through March and into April. Travelers with asthma or other breathing problems should avoid that stretch; everyone else should check IQAir or Air4Thai before committing to outdoor plans.
Rain in May usually clears the haze. The rainy season then runs through summer into October, with green hills and afternoon downpours.
I would choose the cool season for an easy initial visit, but I would not treat a cheap dry-season booking as automatically clever if the dates sit inside the haze period. Check the air before you congratulate yourself on the booking.
Fly in, then consider the sleeper back to Bangkok
Chiang Mai railway station gives you another way to build the return. Overnight sleeper trains run between Chiang Mai and Krung Thep Aphiwat Central Terminal in Bangkok.
The newer air-conditioned sleeper cars make up into beds, with wider lower berths that tend to disappear early. Tickets are sold through the State Railway of Thailand at dticket.railway.co.th, which has an English interface. Resellers sell the same berths with a markup.
Sleepers fill during the cool season and around peak travel periods, so this is not the part of the trip I would leave until everything else is booked.
For a mixed itinerary, flying into Chiang Mai and taking the sleeper back to Bangkok can make sense: the train replaces an airport run and turns the overnight leg into the transfer itself. The point is not that rail wins. The point is that you should decide the connection before the booking decides it for you.
