Thanks to its fast growing economy, Ho Chi Minh is well connected to the world by a vast amount of airlines. Operating airlines to Ho Chi Minh city includes big names such as Air France, Japan Airlines, Asiana, Lufthansa, United Airlines, etc.
These airlines serve direct flights to major cities in Asia (Hongkong, Tokyo, Beijing, Seoul and all Southeast Asian capitals), Europe (Frankfurt, Paris, Moscow), Australia (Melbourne, Sydney) and America (San Francisco). The recently renovated international terminal made Tan Son Nhat airport the largest, both in size and capacity, among all airports in Vietnam.
Domestically, there are daily flights from major cities such as Hanoi, Danang, Hue. Others have 3-4 flights per week to Ho Chi Minh City, depending on seasons. There are only two airlines serving domestic routes: Vietnam Airlines and Jetstar Pacific Airlines.
Bus runs from Phnompenh to Ho Chi Minh City everyday, crossing Moc Bai border or ferry transfer in Chau Doc. The trip is about 6-7 hours and costs about $12.
For intercity travel, you can book a ticket from Mai Linh or Phuong Trang from almost any destinations. These two companies are reliable in terms of timing and bus quality. Other options include Sinh Cafe or Hanh cafe though there have been reports for scams and passengers pick-up along the way. Check out 2 main bus hub in Ho Chi Minh city Mien Dong and Mien Tay bus station.