On August 31, I am flying out of Washington, DC to Ho Chi Minh City, with a connection in Beijing (all via Air China). My connection will occur on September 1st, and by the time I arrive in Vietnam, it will then be September 2nd. I do have a visa for Vietnam, but it becomes valid on September 1. Will this be a problem when boarding my first leg on August 31 in Washington, DC? I wouldn't think it should as my visa will be valid when I actually arrive in Vietnam. Also, by the time I check in on August 31, it will already be September 1st in Vietnam (due to the 11 hour time difference). As a side note, I also have a valid Chinese visa.