Lake Constance family holidays is one of the best family holidays in Germany. The best in this sense is the section around Überlingen and Meersburg to Friedrichshafen. There is so much entertainment there that you can’t visit it all in one vacation.
The Swiss side is less interesting and attractions are further from the shore. Moreover, there are steep slopes and more depth. But in the Rhine Delta, the lake is shallow, and it is great for swimming with children.