How best to do one day in Santorini

Taxis are very hard to come by on Santorini. There is a funicular that can at least get you up from the ferry terminal to Fira. There is a bus station in Fira as well that would take you straight to Oia. Buses can be crowded and the bus station is a little chaotic but the buses are pretty clearly labeled as to where they're going and they're cheap. Just make sure when you get to Oia you check on what time the buses will be going back to Fira. That doesn't mean they'll leave on time though so be at the bus stop early to be safe. You would then take the funicular in Fira back down to where your boat is docked but another warning is that this line can be very long. When it's all said and done, you may only have a couple hours in Oia but it's worth it.

How available taxis are depends on when you plan to be there. You will come up the cliff by cable car. When you exit the cable car building turn left away from the sea and walk to the end of that short lane. Turn right and up ahead on the left you'll see a short flight of steps down to another lane that will lead you out to the main road. Turn right onto the main road and walk downhill about 400 yards, continuing past the main square in Fira where the outdoor cafes are located side by side, and on the left you'll see the taxi office in a parking lot. And FYI, the bus square is just past the taxi office down on the left. A taxi will take you right to Ammoudi for around €20 so you can dine at Katina's, and they will call for a taxi to return you to Fira or take you up into Oia where you can find a taxi at the bus square when you're ready to return to the cable car building.

What Rosie called a "funicular," is called a "tram funicular" and a cable car on the signs. I mention this because it is not a cable railroad, the usual definition of a funicular.

If you have seen pictures, you know that the cruise ships dock out away from the dock at the bottom of a very steep and deep part of the caldera. Other smaller boats take people from the cruise ship to the dock to get the cable car to the top.

There will be waiting and there will be walking. There will be some stairs of some sort no matter where you go. In fact, the steps just to get to the cable car are described as "quite a few" and "long and low," but getting steeper, especially as you get to the cable car itself.

Maybe you could contact the restaurant about getting a taxi between Oia and them. I didn't see any water taxi options, but they would know about that, too. I sure wouldn't want to walk down or up the steps or road to and from the restaurant either.

One description I saw said it was about 300 steps from Oia down to the Amoudi restaurants (and about 580 between the tender dock and Fira).

P.S. We saw almost no one riding animals anywhere, and the few animals we did see were mules, not donkeys.

There is no water taxi from the tender dock to Oia's Ammoudi Bay. There used to be, but is no more.

I seriously doubt that the restaurant will arrange a pickup for you at the cable car building, but if you have access to a mobile phone with a Greek SIM card you can call 22860-22555, the number for the taxi company. If you are using a phone from home call 011-30-22860-22555. I'm sure they'll send someone to pick you up but it will most likely cost more than if you walked to their office. Be sure to set the price if you call them.

We had one day on a cruise. We took the funicular/tram up, walked around town for a short bit, and took the public bus to Oia. Locals can direct you to the bus area. It does seem somewhat chaotic, but it's pretty straightforward. Find your bus, get onboard, and pay the attendant was he walks up and down the aisle. We took the bus back and the funicular down to the ship. It was all easy enough and we enjoyed our day. Ours was a smaller ship, and docked very near the funicular (I don't recall tendering, but ?) . I believe we were told other, larger ships dock elsewhere, but we were the only ship there that day in October.