This is a must see if you are in Florence! The Cinque Terre walk is 9km of winding hills and valleys, following the amazing coastline through '5 terraces' - 5small villages that the walk passes through. From Florence it is approx 2hr train journey to the start of the walk and although its a long and exhausting day - you do need a reasonable level of fitness to complete the walk - it is well worth it! You will need to pay for your return train journey, the train leaves regurlarly from Florence and its best to get the earliest possible - 6or7am. It will cost you approx 40euro, you will need to change trains once, its basically changing platforms and the crowds will show you where to go! The train stops at each village you can hop on and off as you like.
You will also need to pay a 'national park fee' which you can pay on the walk. You will come little huts set up for this purpose. This is about 5euro per person.
You can do sections of the walk at a time and spend a night or two in each village, breaking the walk up and allowing the legs more time to recuperate! but it can be done in one long stretch, it will take you approx.5hours. And the swim in the beautiful clear ocean when you reach the end point is a very sweet reward! aswell as the train to carry you back to Florence One of the highlight of this region, I highly recommend it.