According to Mustgo, an online booking platform with more than 2,000 hotel partners nationwide, air ticket prices increased by 15-40% from the first half of last year due to increased fuel prices and lack of aircraft.
This affected travel trends with tourists heading for beaches conveniently accessed by road.
In the south and south-central regions, Nha Trang, Phan Thiet and Vung Tau reported high occupancy rates on weekends and occasionally even running out of rooms.
But data from Mustgo showed Nha Trang only received a small number of visitors from the north due to the impacts of high airfares.
Some hotels in Quy Nhon too said there were almost no guests from the northern region, and their parking lots were always full because guests arrived by car.
In the northern region, Mustgo recorded high room occupancy rates in Quang Ninh and Hai Phong, home to world-famous bays known for luxury cruise tours.
Pham Anh Vu, marketing director of Viet Tourism Media Company, said travel by private car for tourism increased in the first half.
Tran Quoc Hung, head of Mustgo's product development department, said: "The factor that greatly affected domestic tourism in the first half was high cost."
Occupancy at high-end resorts and hotels decreased by 20% year-on-year despite their unceasing promotions.
Many preferred budget-friendly options, Hung added.
Statistics from Viet Tourism Media Company showed that summer travel by train increased by 40% year-on-year amid the wariness over airfares.
Mustgo said the airfares would remain a big factor for the rest of the year.
Tourism insiders gave a positive forecast for the outbound tour market with destinations such as China, Thailand and South Korea becoming increasingly popular thanks to competitive prices.
There were 66.5 million domestic visitors in the first half of this year, up 4%.