Friesland is very suitable for cycling. Higher elevations see rare here. In many places there are bicycle rental, for example if you want to have a bike for a day or an afternoon, there are plenty of options.
Of course you can bring your own bikes, please keep in mind that seats 28 inch wheels on board is limited, better are handy little folding bicycles that can be transported without problems easily.

From the year 2016 it is possible to rent our folding bikes (while stock lasts). You can specify this when booking, we will make sure that they are on board with you. (Max. 2 or 4 per vessel):

Prices bicycles:

1 week, weekend, shortweek   2 weeks, 10/12 days
30,00 Euro   50,00 Euro