Bangkok Suvarnabhumi Airport (BKK)

One roof, lettered concourses, one satellite

The passenger terminal is one building stacked in layers: check-in fills a single long hall upstairs, arrivals and the baggage belts sit below it, and the concourses run off a central spine lettered in order, so the letter on your boarding pass tells you how far you will walk. The far ends are a genuine hike, with moving walkways most of the way, and the transfer desks sit where the spine meets the concourses rather than out at the gates.

The satellite concourse stands apart among the aircraft stands and is reached only from inside security, by an underground automatic shuttle running between the two buildings around the clock. There is no way in or out of it landside: if your gate is out there you clear departures in the main building first, ride out, and come back the same way on arrival. Worth knowing before you plan a tight connection.

Into the city: the rail line, the meter queue, the expressway

A station in the basement of the terminal carries the airport line into town, calling at a handful of city stops on the way. At Makkasan a covered walkway hands you to the metro; at the end of the line, Phaya Thai puts you on the Skytrain. Tokens are sold at the gate line and contactless bank cards work on the barriers, so a short-stay visitor needs no stored-value card. The line stops overnight and restarts early.

The public taxi rank is a level below arrivals and runs on a ticket: take a number at the counter, walk to the bay it names, and the meter goes on before the wheels move. On top of the fare you pay an airport surcharge and any expressway tolls, and nothing else. Anyone approaching you upstairs with an offer is not part of that queue, and ride-hailing has its own marked pickup point.

The border: the arrival form, the gates, the queue

Thailand asks every foreign arrival to file a digital arrival card online shortly before travelling; it is free on the official immigration portal and comes back as a code to keep on your phone. Automated gates have opened to a short list of passports, but only for travellers whose biometrics are already on file from an earlier arrival, so a first visit means a staffed counter whatever you hold. What your nationality needs to board belongs to the entry rules for Thailand.

Layovers, showers and a night in the terminal

Long layovers are unusually well served. A transit hotel inside international departures sells rooms in blocks of hours, lounges with showers sit along the concourse spine, and the quiet corners upstairs make a short overnight survivable for free. Food follows a rule here: the further from the boarding gates, the better and cheaper it gets, and the canteen-style food court downstairs is priced for the people who work at the airport.

Landside, a full-service hotel joins the terminal by an underground walkway with capsule rooms along the same passage, and a ring of cheaper hotels off the airport road runs its own shuttles. Whether leaving the airport is worth it depends less on the clock than on the train's operating hours: with a full day in hand, the rail line and the river together put the old royal city within comfortable reach and back.

Onward: the other airport, the coast, the rest of the country

Bangkok's second airport lies on the opposite side of the city, and Suvarnabhumi's own answer to that is a free shuttle for passengers holding a connecting boarding pass, sign-posted outside arrivals and taken as it comes rather than booked. Without such a ticket the public route chains together separate rail systems and a taxi crosses the whole metropolis, so treat the transfer as a leg of the journey rather than as a layover.

Coaches to the eastern beaches and down the coast leave from the airport's own transport centre, reached by a free shuttle, with their ticket counters on the lower level of arrivals; the car hire desks sit out there too. Domestic flights depart from the same building you land in, which makes Suvarnabhumi a workable hinge for a trip continuing by sleeper train, ferry or overnight bus.

Practical: phones, cash and the tax refund

Connectivity is best settled before you land: an eSIM bought at home is live the moment you switch the phone on, which matters when you are trying to find a driver or read a platform sign. Cash machines in the halls charge a flat fee per withdrawal whatever the amount, so one larger withdrawal beats several small ones, and you should decline any offer to bill you in your home currency — the rest of that arithmetic sits with money in Thailand.

On the way home, two counters catch people out. Shoppers claiming the tourist tax refund present the goods to customs in the departure hall before the bags are checked in, then collect from the refund desk beyond passport control, so the order is inspection first and check-in second. Assistance for reduced mobility is arranged through the airline in advance and met at marked points, and left luggage is landside, which means collecting it before you head for departures.