Do I really need an onward flight?

Yes. Airlines are often fined for carrying passengers who don't have proof of return or onward travel, so they may prevent you from boarding your initial flight without it.

Can I cross land borders visa-free?

Yes, but check the 'entry by air' versus 'entry by land' rules for each country, as some countries limit the number of visa-free land entries you can make per year.

How to travel Southeast Asia without advance visas

Most nationalities can travel Southeast Asia visa-free or via visa-on-arrival for stays between 15 and 90 days. Focus your route on Thailand, Malaysia, Singapore, and Vietnam (e-visa) to minimize paperwork while maximizing movement.

Verify your exemption status. Check the official embassy website for your passport's country of origin regarding Thailand (30-60 days), Malaysia (90 days), and Singapore (90 days). These are the easiest hubs to enter without pre-planning.
Use e-visas for secondary destinations. For Vietnam, Cambodia, and Laos, apply for an e-visa at least 7 days before your arrival. Do not rely on 'visa-on-arrival' at land borders, as queues can be hours long and they often require exact cash in USD.
Prepare proof of onward travel. Immigration officers often ask to see a flight out of the country. If you don't have one, use a service like 'OnwardTicket' to rent a legitimate, verifiable flight reservation for 48 hours for roughly $12.
Keep digital and physical documentation. Carry four passport-sized photos in your wallet and keep a digital folder on your phone containing your passport bio page, e-visa approvals, and vaccination records.

Do I really need an onward flight?: Yes. Airlines are often fined for carrying passengers who don't have proof of return or onward travel, so they may prevent you from boarding your initial flight without it.
Can I cross land borders visa-free?: Yes, but check the 'entry by air' versus 'entry by land' rules for each country, as some countries limit the number of visa-free land entries you can make per year.