The BTS Skytrain, MRT subway, river boats and taxis cover almost everywhere you'll want to go.
The elevated BTS and underground MRT are the fastest way across town, avoiding Bangkok's notorious traffic. Rechargeable Rabbit cards work across both networks in most cases.
The Chao Phraya Express Boat is a scenic and practical way to reach riverside sights, while canal boats on Khlong Saen Saep cut across town away from the road network.
Metered taxis are cheap but drivers may avoid the meter for tourists — insist on it or use an app like Grab, which shows the fare upfront.