Long Thanh International Airport is being built in Dong Nai Province at a cost of over VND336 trillion (US$12.7 billion) in three phases.

Phase one is expected to be completed this year and begin operations in mid-2026 with a capacity of 25 million passengers annually.

The Airports Corporation of Vietnam (ACV), the state-owned firm that operates all 22 commercial airports in Vietnam, has proposed two scenarios: moving all international flights to Long Thanh straightaway or shifting only long-haul international routes there and keeping short-haul flights at HCMC’s Tan Son Nhat.

The ACV points out that Tan Son Nhat has been overloaded for years with both its limited space, causing congestion and reducing service quality, while Long Thanh is designed for long-term capacity of up to 100 million passengers annually when all three phases are completed.

Even in its first phase, it can handle 25 million passengers with modern infrastructure, spacious terminals and automation enabling smooth passenger flow, it says.

Its location is also better, separated as it is from residential areas, without night-flight restrictions and connected by highways and ring roads with metro lines planned in future.

Shifting international flights to Long Thanh will ease pressure on Tan Son Nhat and improve domestic services, it says.

The Civil Aviation Authority of Vietnam and many international airlines largely agree with this argument, saying moving all international flights to Long Thanh will simplify management and optimize resources.

But Ngo Viet Nam Son, an architect who has been involved in planning several international airports, says the two airports can operate independently, handling both international and domestic flights.

He says if all international flights are moved to Long Thanh, the two airports will become interdependent: domestic passengers arriving at Tan Son Nhat will then have to travel an additional 40 km to connect, and vice versa.

“When the transport system is not yet complete, this inconvenience could reduce the appeal of the new airport.”

He cites the example of Montreal, Canada.

The city once built Mirabel Airport on a large scale and shifted all international flights there from Dorval Airport, 55 km away, but due to the long distance and poor connectivity, airlines were reluctant to operate from there.

Authorities eventually had to move international routes back to Dorval and Mirabel is now used only for cargo transport.

Son says airport construction must go hand in hand with transport projects, the most urgent being highways and ring roads.

While metro and rail links between Ho Chi Minh City and Long Thanh are necessary, they require large budgets and a long time, and so priority should be given to key road projects that can be completed quicker, he says.

Vietnam Airlines’ proposal to keep some short-haul international flights at Tan Son Nhat and move long-haul and some domestic routes to Long Thanh is a reasonable plan, he says.

Domestic passengers at Tan Son Nhat airport in HCMC. Photo Read/Giang Anh

Concurring, Phan Le Binh, chief representative of OCG Japan, which provides transport, urban development and environmental consultancy, says Tokyo’s experience is also instructive.

Haneda, 26 km from downtown, used to be the only airport in the Japanese capital.

When it became overloaded, in 1978 the government built Narita Airport 75 km away and moved international flights there.

Despite highway and metro connections, Narita’s distance meant costly and time-consuming travel into Tokyo, affecting efficiency.

After reviewing passenger and airline needs, Japan added a new runway at Haneda in 2010 to handle international flights again.

Today both handle international and domestic flights with coordinated distribution, allowing the two airports to complement one another.

“Operating international flights at two locations requires more staff and equipment and costs more, but Japan chose this for passenger convenience,” Binh says, recommending that Vietnam should prioritize passenger convenience when dividing operations between the two airports, especially as Long Thanh–HCMC connections remain limited.

Assoc. Prof. Dr. Nguyen Thien Tong, former head of the aeronautical engineering department at the Ho Chi Minh City University of Technology, says international flights should remain at Tan Son Nhat for at least a few more years, especially as the new T3 terminal built at a cost of VND11 trillion has increased the airport’s capacity to 50 million passengers a year.

“Only when connections are complete or Tan Son Nhat is too overloaded should flights gradually move to Long Thanh.”

He suggests moving all cargo, logistics and aviation services first to Long Thanh to ease pressure on Tan Son Nhat.

He recommends following the international practice of letting separate companies manage airports. This contrasts with the current system where ACV is solely in charge. He argues this would give airports the independence to attract more airlines, enhance service, and improve efficiency.