Santorini is another great day trip to take while on Crete.
You can take a boat from Rethymno, Chania or Heraklio or a speedboat like catamaran from Heraklio or Chania.
It is not a cheap way to spend a day, but worth every penny.
I find Santorini too expensive to go there for a week long vacation but it is perfect to go for a day and see the island.
When you get off the boat I recommend to take one of the trams to get you fast on the top of the crater. When there jump on one of the local buses to take you down south of the island. After Just few stops you will get to Akroti, a nice little town that looks exactly like famous Oia but the commute is shorter and you will avoid most of the tourist.
From Akroti you will see the whole island to the north with the Oia town (if the weather is nice).
You can have a nice relaxing day in Akroti, with a great lunch.
You should catch a bus and give yourself at least 1 h and 30 min before the boat, so you can make it on time and walk down or take a donkey ride down the crater to the boat.
If you have an extra time, enjoy a cold frappuccino and gift shopping on the harbour.
If youve seen pretty much all of Crete and wondering what else to see and do I highly recommend doing a day trip to Santorini if you have time.. Its amazing!
We went to a local tourist office in Gouves and booked with Armillis tours. It cost 92 EUR each and this includes return trip from heraklion on the Fastcat boat and only takes 1hr 1/2 to get to Santorini and back (normal trip takes about 3-6hrs i think each way). Once you get to the port in Santorini, the tour bus awaits. The tour includes passing through 3 towns, Pyrgos, Ia (the picturesque town of them all) and Fira. You get about 1 hr in Fira and Pyrgos and 2 hrs in Ia. The tour guide is extremely informative and very friendly.
The only downside was that we went in the middle of August and it was extremely hot about 40 degrees so it is really hard to walk around in that sort of heat esp since there isnt a whole lot of shade unless you go into a restaurant or shop. Thank god the bus is airconditioned. Id say its best to go in spring when the weather isnt too overbearing.
If you do decide to do the tour its better to book as soon as you arrive in crete to get the day you want as we nearly didnt get a place at all. The tour is a bit pricey but it is definately worth it since Santorini isnt the easiest place to get to and see so you might as well do it from crete whilst you have the chance!
From Crete you can book a one day cruise. It costs 68 euro (in 2003). So quite expensive. Breakfast and dinner are included. If you book the one of 55 euro then dinner is not included in the price. On the boat (The Atlantis) itself they offer you two excursions (20 euro pp). I would advise you to book them, because you don't have a lot of time on the island itself to search things out for yourself. You go 5 hours and 5 hours back, so you are only 5 hours maximum on the island itself.
It's quite a hurry all the time but at least you will have an impression of the island which is very beautiful . I would not advise you to stay for example for one week on the island, there is not a lot to see and to do, unless you want to lay in the sand for a week. And it's very expensive .Villages to see: Pyrgos, Oia (certainly because here you have those white houses with blue roofs) and finally Fira (where the boat leaves).
I have put some pics in a small travelogue.