Where is the nearest customs to BeiHai and how long does it take to travel there?

The closest one is Beihaigang Port, which is newly put into use in Apr. It is just in the city and you can take a taxi there. Moreover, I know the Dongxing International Port, boardered with Vietnam. It is around 200km away and takes 3h to arrive.

Thanks Nancy. Can I take a bus to Dong Xing china/Vietnam customs and walk over to Vietnam? And make an immediate U-turn to enter China again? On the same day? How much would the bus ride cost, one way?

Also, does BH city have natural disasters, like typhoon, since it's near Hainan? Or is it protected by the bay?

Yes, James. Buses are available. You can easily take a long-distance bus at local Nanzhu Bus Station to Dongxing City first in 2-3 hours. Take a motor or taxi to the international border to go through the immigration to Vietnam.

Generally, it is doable for a return trip, because the first bus to Dongxing leaves at 07:00 (CNY65 per person) and the last bus gets back at 18:50 (CNY68 per person).

At last, you'd better make it clear if you need any paperwork/document to present at the border. Good trip.

You've been a great help, Nancy.