The approval letter is one of the compulsory documents that you need to have before arrival. This letter allows the applicants to get visa at the “visa on arrival counter” when arriving Vietnam international airports.

Therefore, you can just enter Vietnam by using the approval letter through 6 international airports:

• Noi Bai international airport in Hanoi city
• Tan Son Nhat international airport in Ho Chi Minh city
• Cam Ranh international airport in Nha Trang city
• Da Nang international airport in Da Nang city
• Cat Bi international airport in Hai Phong city
• Phu Quoc international airport in Phu Quoc island

The approval letter is not accepted through any sea ports. In addition, there is no Visa On Arrival counter at sea ports to get the visa stamp. If you are going to enter Vietnam by ship, you can consider to choose Electronic visa (E-visa). This visa can also applied online, can enter through sea ports and stay for not more than 30 days with single entry.

See more about Vietnam Evisa.