The Chao Phraya Express and canal boats are cheap, scenic, and genuinely useful for getting around.
A public commuter boat service running from south Bangkok to Nonthaburi — stops at riverside piers near major attractions; orange flag = tourist route; 15–40 THB.
Blue flag/BTS 'tourist boat' makes fewer stops, costs 50 THB/trip or 150 THB/day pass — worthwhile if doing multiple riverside attractions in one day.
Faster than buses through traffic — narrow long-tailed boats through Khlong Saen Saep serve from eastern Bangkok to downtown; 9–20 THB; chaotic but authentic.
Short cross-river ferries (3–5 THB) connect the two banks at many points — useful for reaching Wat Arun from the east bank or ICONSIAM by river.
Wear clothes you don't mind getting splashed; step on and off quickly; have small coins ready; rush hours (7–9 AM, 4–7 PM) get very crowded.
