Caravan tours between cultural and historic sites in the three countries have faced challenges.
During a recent "investigation trip" by officials, they discovered that roads from the border gate in Vietnam to Cambodia's Kratie extend 230km but are not in good condition.
In addition, many enterprises want to organise tours but have been unable to do so because of immigration procedures.
We need strong links between the three nations to deal with immigration. In addition, more investment for infrastructure, including roads, services and rest stops, is needed, said Ho Tan Cuong, vice director of central Quang Nam Province's Culture, Sports and Tourism Department, who took part in the investigation trip with other officials.
He suggested a tourism route that could begin or end at Angkor Wat in Cambodia to Laos' Vat Phou temple, to the Central Highland provinces in Vietnam to learn about the gong culture. The final stop could be the My Son sanctuary and the historic town of Hoi An in central Vietnam.
Tourists could enjoy the cultural values of three countries via road and air, Cuong added. Tourism on roads from Vietnam to Laos and Cambodia is now convenient.
In addition, Cambodia and Laos have become more attractive to many Vietnamese tourists.
For the first 10 months of the year, more than 700,000 Vietnamese visited Cambodia.
At the 32nd annual meeting on tourism development among the three countries, held in Kampot, Cambodia, early this month, the Asian Development Bank (ADB) announced a support loan of US$100 million for tourism infrastructure projects in the subregion.
The funds will be used for seaport construction, waste water treatment for tourism areas, green tours on sea, and tourism development with the participation of local communities.