The animals, together weighing 140 kilograms, were found in a hidden box in the duo’s 16-seat van by officers from Ha Tinh Province.
The vehicle had passed the Cau Treo border with Laos when it was flagged down by the police in Tay Son town.
Phan Van Dung and Nguyen Thi Lai, both 41, told them they had been hired by a Laotian to transport the animals from Laos to his partner in Vietnam.
The police arrested the two and seized the animals.
Pangolin trafficking is not rare in Vietnam, where it is legally protected and categorized as endangered.
The shy, tiny creature, which resembles a scaly anteater, is the world's most heavily trafficked mammal despite bans. Pangolins are sought after in Vietnam and its neighboring countries for their meat and the alleged medicinal properties of their scales.
Of the 10 countries and territories in the world with the highest trafficking rates, seven were in Asia -- China, Vietnam, Malaysia, Hong Kong, Thailand, Laos, and Indonesia – a 2017 study by wildlife trade monitoring group Traffic and Australia’s University of Adelaide had found.