In the morning I went to small pier in Nong Khiaw and bought a ticket to Muang Khua, which is another small town in the north of Lao. From there it should be easy to get a bus to Dien Bien Phu in Vietnam.
The boat started at 10:30 from Nong Khiaw. Till the first stop the boat was very full, so full that water came in and I think even the driver was anxious that there is too much load on the boat and got quite nervous.
But after that it was a relaxing trip, just once we had to bypass a dam by bus.