Vietnam’s Tan Son Nhat International Airport (Ho Chi Minh City) and Noi Bai Airport (Hanoi) conduct drug screening operations that include customs drug-detection dogs, baggage scanning, and random passenger checks. Transiting through Vietnamese airports after cannabis use in Thailand or Cambodia is a documented risk scenario. Do not transit through Vietnam within days of cannabis use without understanding clearance timelines.
THC Clearance Timelines
THC metabolites remain detectable in urine for: 3-4 days for single casual use; 7-14 days for weekly use; 30+ days for daily heavy use. Blood tests detect active THC for 3-4 hours after use. Saliva tests detect THC for 24-72 hours. Hair follicle tests detect THC for up to 90 days. At Vietnamese customs, the primary method is urine testing of any individual pulled aside for investigation — not routine passenger screening. The risk at airport is primarily from suspicious behaviour or accompanying drug-detection dogs flagging luggage.
Visitors who have used cannabis legally in Thailand or Cambodia and plan to fly to or through Vietnam should plan for a minimum 7-day clearance period for casual use and 14+ days for heavier use before transiting Vietnamese airports. If your travel itinerary does not allow for this, consider alternative routing that avoids Vietnamese airports entirely.
Full Drug Test Guide
For comprehensive THC detection and clearance information including test type breakdowns, frequency of use factors, and a complete Asian airport risk map, see our dedicated drug test guide.
Drug Test After Vacation: Complete Guide →