Should I book all my transport in advance?

Book international flights and long-distance trains 3 weeks out. Book buses and local ferries 24-48 hours ahead via your hostel front desk.

Is 3 weeks enough to see all of SE Asia?

No. Trying to visit Thailand, Vietnam, Cambodia, Laos, and Indonesia in 21 days will leave you exhausted and spending all your money on regional flights.

Planning a 3-week backpacking route through Southeast Asia

Focus on the 'Banana Pancake Trail' loop covering Thailand, Laos, and Vietnam to minimize transit time. Spend no more than 4 days in each major location to avoid burnout and keep your transport costs under $300 total for the trip.

Choose your anchor city. Start and end in Bangkok. It is the cheapest regional flight hub. Booking a multi-city flight into Bangkok and out of Hanoi or Ho Chi Minh City saves you a full day of backtracking.
Map your transit legs. Limit yourself to three countries. Use budget airlines like AirAsia or VietJet for long distances (e.g., Bangkok to Hanoi) to save 12-hour bus rides. Use night trains for mid-distance travel (e.g., Bangkok to Chiang Mai) to save on a night of accommodation.
Set a hard pace. Allocate 3 days per city. Southeast Asia transport is slow and prone to delays. If a bus trip is scheduled for 8 hours, budget for 12.

Should I book all my transport in advance?: Book international flights and long-distance trains 3 weeks out. Book buses and local ferries 24-48 hours ahead via your hostel front desk.
Is 3 weeks enough to see all of SE Asia?: No. Trying to visit Thailand, Vietnam, Cambodia, Laos, and Indonesia in 21 days will leave you exhausted and spending all your money on regional flights.