Beautiful lagoon and island with amazing views from the castle on Gramvousa. unfortunately it was very windy and the sea was quite rough that day so the boat ride heading out was rocky, and several people were seasick. Keep in mind in case you don't do well on boats!
Great tour only problem we still had to pay 16 € per person for boat ticket.
Gramvousa has amazing views and Balos is just an unbelievable place to go for a swim.
Chrysi is beautiful and Altino Travel were fantastic. I would recommend booking this locally as it is only 14 Euros for the whole trip if you pay direct on the day! We were the last on the coach so it only took around 1.5hrs from Sissi to Ierapetra, then an hour long boat ride (the boat gets v busy) before arriving on the island. We had about 3-4 hours on the island. The guides kept announcing over the boat's tannoy that the pick-up time would be 4pm, then 4.30pm, then 5pm, then eventually 3.45pm - slightly unorganised. Tips for Chrysi: it can get very windy, two loungers and a parasol will cost you 10 Euros and also there are only a couple of non-flushing portaloos on the island.
I was really disappointed with my crete island day trip. We paid 227 for 2 people, and from the description it looked good - however all we got in the end was a minibus pick up / drop off from our hotel and a boat ride to the various places. The boat was massive and had hundreds of people on it. There was no tour guide or explanation about the different places we visited. For the amount we paid i would have expected it to feel more personal but we could have just booked the tickets for the boat and a transfer for cheaper ourselves. Getting off the boat at the various places took 30mins and you had to get back on 30mins early if you wanted a seat because there were so many people which really cut down the time you could have at each place. I definitely would not book this trip through viator - i would just book it myself. i was really disappointed.