Bangkok Airport Info 
Your arrival at the main terminal building may be through a terminal gate or bus gate, depending on your airline and flight route. For bus gates, you will be brought to within a few hundred metres of Immigration (located on the second floor) whereas via the terminal gates, you may have to walk for quite a bit before getting to Immigration.

Airport Tax
For international departures, you are no longer required to pay the airport tax at one of the vending machines located in front of Passport Control. The 700 baht tax is already included in the price of your air ticket.

Suvarnabhumi Airport Link
The Airport Link (06:00 - midnight) is the fastest and most efficient way to transfer to downtown areas. For 150 baht, the journey on the Express Line takes only 15 minutes, from the airport to the City Air Terminal (Makkasan Station). To transfer to the BTS, get off at Phaya Thai Station.
City Line makes eight stops (Suvarnabhumi Airport, Ladkrabang, Tha Thap Chang, Hua Mark, Ramkamhaeng, Makkasan, Ratchaprarop, Phyathai) and takes about 30 minutes.

Metered Taxi (or Taxi Meter)
From the Arrival Hall on the second floor, you will need to take an elevator down to the first floor to find the designated taxi stands at Entry Gate 4. Simply queue up and tell your final destination to the booth officer, then a taxi driver will escort you to his vehicle. Please note that you need to pay the driver an extra 50 baht courtesy fee, on top of all toll way fees and the final taxi fare. Taken all these fees into account, it should cost you a total of 350-400 baht for a 40-minute ride to downtown Bangkok. Service is available 24 hours.

Airport Express Bus
The Airport Express Bus, at 150 baht flat rate, is probably the best deal if you are heading to one of the destinations along the four available routes: Silom Road, Sukhumvit Road, Khaosan Road and Hualampong Railway Station. The journey should take about 45 minutes. For detailed route information, contact the service counter located on the first floor, at Entry Gate 8. The service runs from 05:00 to 24:00 daily.

Airport Limousine
Most travellers consider this a rip-off. However, if you prefer a first-class car journey, this is the only way to go. From the arrival hall, locate the nearest service counter (all located on the same floor), and choose from the eight available vehicles. The rates vary according to the type of vehicle and the distance. For a 40-minute trip to downtown Silom, Rajathewi, Sukhumvit or Phayathai, the flat rates start from 950 baht in an Isuzu MU-7 to 1,200 baht in a Toyota Commuter or London-style cab to 2,200 baht in a BMW 7 Series. Service is available 24 hours.