Two of the men were nabbed at around 6 p.m. while they were driving a car along National Highway 8A near the border.
Upon searching their cars, border guards and customs officers discovered 10 kilograms of heroin, 45 kilograms of methamphetamine, 6,000 amphetamine pills, two handguns and 50 bullets.
Half an hour after their arrests, Ha Tinh officials caught four more Laotians on the national highway.
While they were not carrying drugs, they have been determined to be the other two's accomplices, responsible for scouting ahead and alerting the duo should any issue arises.
The six Laotians have admitted to being members of a trans-national drug trafficking ring that acquires drugs in Laos before smuggling them into Vietnam through Huong Son District's Cau Treo border gate.
Ha Tinh police are investigating further.
Vietnam is a key trafficking hub for drugs from the Golden Triangle, an intersection of Laos, Thailand and Myanmar, which is the world's second largest drug producing area after the Golden Crescent in South Asia.
Drug trafficking and consumption have persisted and worsened in Vietnam over the last few years, despite the country having some of the world's toughest anti-drug laws, including death sentences for drug smuggling and trading.