Bangkok has two airports and this matters
The first thing to know: Bangkok has Suvarnabhumi (BKK) for most international flights, and Don Mueang (DMK) for budget domestic and some regional flights. They’re 30km apart. Double-check which airport you’re arriving at before planning anything.
Suvarnabhumi to Bangkok
The Airport Rail Link is the right answer for most people — ฿45–145 depending on destination, 30–45 minutes to central Bangkok, runs until midnight. It connects directly to Phaya Thai (BTS Skytrain interchange) and Makkasan (MRT interchange). Clean, air-conditioned, no traffic. I use this every time I arrive at Suvarnabhumi.
Metered taxi to central Bangkok: ฿200–350 plus ฿50 expressway toll and ฿50 airport surcharge. Can be 45–90 minutes depending on traffic. Use the official metered taxi queue inside the arrivals hall — don’t accept offers from people approaching you outside. — book a Welcome Pickups airport transfer in advance for the best price.
Don Mueang to Bangkok
No train link from Don Mueang, which is frustrating. Options: free shuttle bus to Chatuchak/Mo Chit (takes 20–30 minutes, then BTS from there), metered taxi (฿250–400 to central Bangkok plus tolls), or Grab which works well from here.
The Grab question
Grab officially operates from both airports now. At Suvarnabhumi, there are designated Grab pickup areas. It’s often cheaper than a metered taxi and you know the price before you get in. I’ve started defaulting to Grab from Don Mueang especially.
Late night arrivals
The Rail Link runs until midnight. After that: Grab or metered taxi. Budget ฿350–500 depending on your destination and time of night. Don’t panic about this — Bangkok’s taxis are generally fine when you use the official queue and insist on the meter.