Can I work without a work permit in Vietnam?

Yes you can if you are belong under these common situations:

• Working duration is less than 3 months.
• Members of a limited company which consists of more than 1 member.
• Owner of a 1 member limited company in Vietnam.
• Members of BOD at a joint-stock company.
• Foreign lawyer with a law practice license issued by the Ministry of justice.
• Doing service sales activities for a foreign company in Vietnam