There is a currency exchange on the border in Lao Cai but they will give you terrible rates. There are plenty of ATMS in Sapa and a standard debit or credit card should work. You won't need more than 50.000 dong per person for the ride up to Sapa although the drivers might try to overcharge you.

Some of the businesses in Lao Cai accept dollars and RMB although there is no guarantee. The dollar seems to be the preferred currency in Sapa so you'll be fine up there. Please note that the accepted exchange rate between dollars and dong is 20.000 dong to the dollar.

Hope this helps,

Eddie

no, you misunderstand, I don't have dollars, and if it's not somehow necessary, I'd strongly prefer not to use dollars. Hence me wondering.

Dollars are not needed at all in Vietnam and Edward Snowden's reports are thus a bit out of date. Vietnam Dong is the only currency that can legally be accepted these days in Vietnam, although many tourist related businesses still (discreetly) accept dollars though they are not supposed to. However, Dong are preferred as all prices are quoted in dong and there is no need to bring anything other than a major currency (RMB are fine) for exchange or just use the ATMs.

Dollars are not needed but they are generally the preferred currency in Sapa. Prices are quoted in dong because it is, as you said, the only currency that can legally be accepted. You would do well to take a reading comprehension course.
- Eddie

No, EdwardSnowden, I am very familiar with Vietnam and I can assure you that dollars are not preferred anywhere in Vietnam, they may merely be accepted. Banks in Vietnam now no longer sell you foreign currencies (including dollars) unless you can produce evidence of travel to a foreign country - only moneychangers don't require any such evidence. ATMs only dispense dong - there are no advantages of bringing dollars to Vietnam unless you are traveling directly from America or have them in your possession for some reason.

I think you may need to get a reality check.

That's interesting because last time I was staying in Dalat and Sapa - in 2013 mind you - the owners of both of the guesthouses I was staying in specified a preference for dollars as soon as they saw them in my wallet. Same goes for many of the restaurant owners in both of those towns. Vietnam is notorious for devaluing their currency and misguided Vietnamese are under the impression that the dollar is stable. Please get a clue before leaving another comment.

- Eddie

I think you should get a clue. The OP asked about whether bringing dollars is a good idea - the answer is a clear NO. Also, there are zillions of ATMs in Vietnam, I thus don't see the need to bring any foreign cash at all. Not to mention that many businesses, especially hotels and mid-range and upper class restaurants accept credit cards.

The Vietnamese dong is quite stable having varied only marginally against the US dollar over the past 2 years and is not exactly freely floating against the US dollar. I have worked and traveled in Vietnam many times (probably been there more than 20 times) and have many Vietnamese friends - I think I know what I am talking about.

End of discussion.

I am Vietnamese. End of discussion.

- Eddie

Eddie, bạn nói cho anh ta !