As much as I like Frankfurt Zoo for its convenience, atmosphere and old architecture (I must get some pictures there for a blog post!) I can recommend Opel Zoo just outside Kronberg as a great alternative. Its small and has only about 200 animals, but provides plenty of amusement or just a nice walk for a couple of hours.
The zoo is really easy to find by car – just keep following the A661 all the way until you see it on your left – and there is plenty of parking right in front of the main entrance. There is a bus stop as well, but will take over an hour to get there from Frankfurt.
Keep your expectations low if you have been to a big international zoo, but for small children it is perfectly good and has a large adventure playground to keep them busy at the end.
Ironically, in spite of their efforts to provide interesting large animals, like their newly arrived pair of cheetahs, my favourite was their raven enclosure (odd for a zoo!). The ravens looked really healthy and arrogant and were tearing apart a rabbit when I was there.
Most unexpected at the end was a steak restaurant (Lodge Beef) outside the main entrance. This place is going to be the highlight for many Dads. I was very impressed with range of meats on the menu. I can’t believe that you would ever need to book a table given the location, but actually it is a well known and in demand restaurant popular across the frankfurt area so it might be worth it if you are definitely planning on eating there. Prices are a little high but the quality and the panorama views over the Taunus make it well worth it especially at sunset.