I generally stick to ship-sponsored excursions, but yes, I have seen taxi cabs every place the ship docks or the tenders land.
I have seen advice here many times to be careful and be sure to negotiate the price before you get in.
We have been traveling in Europe for about 30 years (both on and off ships) and very seldom use tours (we prefer rental cars, trains, local buses and taxis). If you post your actual ports I can give you detailed taxi info on each port.
Do you have any knowledge of a public sightseeing tram on the island of Rhodes, perhaps near the City Hall? We are going up to Lindos but wanted to see a little more of the area. Any suggestions or should we plan on walking?
Good Morning Sunshine, Lets talk about these ports. Olbia - I haven't been to Sardinia in about 10 years, but on our last visit there were a few taxis (not many). However, your options are somewhat limited in this port. They used to run a tour that included boat transportation to the Costa Smeralda (Emerald Coast) which is one of those swim, snorkle and beach trips. That probably makes more sense than a taxi here and keep in mind that I normally hate tours.
Palermo - You actually will dock at the port side of town and its possible to get taxis, grab local buses, or walk. Although Palermo is not a great tourist city it does have one very weird attraction called the Catacombe Cappuccini. This is in the basement of a very old monestary (there is actually a monk at the door) where there are literally thousands of skelatons (many are dressed) just laying and hanging around. This place can best be described as macabre, but it is amazing. You can get there by taxi or local bus and I suggest you google the place and read about the details.
La Spezia - There should be taxis, but they will want to negotiate a full or half-day hire for a set fee. Many of the Italian taxis that meet ships do not want the short local fares. We love this part of Italy and I guess many like that its close to the villages of Cinque Terre.
Marseille - You will dock at the port which is located a couple of miles out of town. There will probably be a bus shuttle into town that drops you at the old port which is only a few blocks from the train station. Taxis are expensive in France. You might want to consider just taking the train to Aix en Provence or even renting a car (we often rent cars in Europe) to explore nearby Provence. Marseille is a large city, but most one-day tourists ignore the city in favor of going to one or more of the Provence towns or countryside.
Villafranche - This is the port located close between Nice and Monte Carlo. Using a taxi here would be expensive and not necessarily a good idea. You can walk from the tender pier to the local train station (you will have to climb about 40 steps) where you can grab the local commuter-type train that goes everywhere along the coast from Monte Carlo to Cannes. You might want to research the villages of Eze and St Paul de Vence which are two of my personal favorites. Another alternative to the train is to simply use the local bus system (very convenient for places between Nice and Monte Carlo). I can help you more with this port once you have decided on the places you would like to visit. My DW and I have spent many months in this region of France (and nearby Italy) and could easily live there for 6 months a year if the darn dollar was not so low.
Yes, paella.....a wonderful thing that should be savored for the depth of flavor is has. With one of the many fine wines made in Spain (not always on the plain), it is truly a memorable meal. This is one of those things that fills a person with a sense of well-being.