Bangkok International Airport is located in the north, outside the city. If you have ATM card, you don't really have to change dollars on arrival, you can simply withdraw some pocket moneyfrom any cashier.
There is no BTS metro to the airport. You will have to take a taxi or one of the 3 lines of buses going to the centre.
Wide range of transportation travel between downtown and airport:
1. Limousine, fare starting from 650 Baht 650
2. Taxi, go to taxi stand in front of Terminal 2 Arrival Hall. Fare based on meter plus Baht 50 surcharge
3. Train, Don Muang Railway Station is about 500 metres across Terminal 1. Fare to Bangkok with Ordinary Diesel Train is Baht 5/person.
4. Airport Bus, Air-conditioned airport bus service operate between Bangkok International Airport (BIA) and downtown for 4 main routes. Fare is only 100 Bath per person throughout one single journey.
5. Public Bus, at bus stop in front of the Airport.
6. Airport Shuttle Bus, 2 routes only, Free of charge.
7. Car Rental
Take the taxis from outside the airport - either left or right exit.
Do not take private taxis. The journey downtown is around 40 minutes to an hour depending on the traffic. The total metered cost around 200 baht and if the taxis travel on the
tollway and expressway downtown (faster), there are two charges of 30B and 40B to pay.
On top of that the passenger also has to pay a 50 baht airport surcharge on top of the metered fee.
Caution is that many taxi drivers claim they do not have small change; so do carry them. alternatively ask the driver to go to the nearest convenient store - 7-11 will do the trick, and funny but the taxi driver will suddenly find that he has all the loose change!!!
Therefore it should cost about 300 baht all cost covered. For a hotel limousine it cost about 1000 baht.
From Don Muang International Airport you have different choises to go from there to down town or what ever.
TAXI: A taxi costs you around 300 THB (Baht) and thats around 8 USD. The trip can take from 30min up to 2-3hours depending the time you go. The rushour is very famous...
TRAIN: There is also a train station opposite of the International Airport Terminal 1 (and you can walk from Domestic Terminal). There are not many trains, maybe 1 per hours. The train is very cheap.
BOAT: As far as I know you can also go by boat and you have to go from the airport to the Chao Phraya River and than you can drive down. This I never tried out...
BUS: There are also Buses leaving near the Railyway Station but I never tryed out this because everything is writen in Thai and I takes very long because the bus stopes everywhere...
The old airport of Bangkok is one of the largest airports in the world! I remember that i was walking for 15 minutes to go to outside!
The best entry point to Thailand is the International Airport (Don Muang). They have a very extensive duty free shopping area.
Bangkok airport is not the prettiest airport but it has some nice shops and decorations. Here is a small temple right inside the airport lobby.