Can I extend my visa on my own? Where should I come?

Yes, you can. Their working time is from Monday to Friday and you can come to these addresses.

• Hanoi immigration office: 44-46 Tran Phu, Ba Dinh District, Hanoi.
• Immigration office in Da Nang: 78 Le Loi, Thach Thang, Hai Chau, Da Nang.
• Immigration office in Ho Chi Minh City: 196 Nguyen Thi Minh Khai, Ward 6, District 3, Ho Chi Minh city.