Thanks to the gentle slope, you can cycle along the Elbe either with or against the flow of the water. Due to the predominant north-westerly wind, it’s generally a good idea to plan your trip upriver so you might catch some backwind.
Only the topmost section of the river, near the source, should be tackled downstream. You can reach the Elbe source from Spindlermühle using the chair lift (you can take your bike) or from Vrchlabí by bus. The source is set in the centre of the national park, and the last few metres can only be tackled on foot.