Reading the kids who post to the Lonely Planet board is sometimes interesting. The following doesn't have anything to do with motorcycles doing this crossing, but it does reconfirm that #1 jimoi has the scoop. From Lonely Planet user name lindzoo
QUOTE
I have successfully crossed the border from Vietnam into Laos through Dien Bien Phu - that border IS OPEN TO WESTERN TRAVELLERS IN BOTH DIRECTIONS. Lao visas are available on arrival but Vietnamese visas are not.
From Dien Bien Phu, there is a bus that leaves at 5:30am Monday, Wednesday and Friday morning from the main bus station at a cost of 60,000 VND. This bus takes you through the border crossing and drops you off in Muang Khua, Laos in the early afternoon. Note that this is the ONLY BUS and there are no bus connections on the Lao side of the border. If you aren't on this bus, you're hitching your way to Muang Khua (75 km from the border).
From Muang Khua, it's one full day of travel to Luang Prabang (through Udomxai) and that bus leaves at 9am.
I was told at the Lao Embassy in Hanoi that ALL border crossings between Laos and Vietnam are now open to foreign travellers and Lao visas are available on arrival at all border crossings.
To get from Sapa to Dien Bien Phu, you have to flag down a bus headed to Lai Chau (50,000 VND) by the petrol station at about 7am (they leave from Lo Cai). And then from Lai Chau you catch another bus to DBP (70,000 VND). You can easily do it in a day (and if you get lucky with the connection, you get to DBP by 3pm-ish) otherwise, 6-7pm.
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