How do I get a Vietnam visa from Hong Kong?

You have two options to obtain your visa to Vietnam from Hong Kong:

Option 1. Apply for a visa at the Vietnamese consulate in Hong Kong:
Address: 15/F, Great Smart Tower, 230 Van Chai Road, Wan Chai
Tel: (852) 2591 4517 or (852) 2591 4510.

Visa forms may be obtained by sending a self-addressed, pre-stamped envelope or faxing to the Number: (852) 2591 4524. 
Fee and Duration: Tourist visas cost between $30-80, depending on the length and number of entry. 

Option 2: Apply for a visa-on-arrival. Note that this type of visa applies to air travel only, and it costs $45 - 85, depending on the duration of stay ad number of entries. The process of applying online at a travel agency is very fast and you do not have to show up at the embassy to submit the application.