One day at port in Salerno

Whether to attempt both in one day, especially on your own, depends on a few things.

-How well you deal with heat. Because that part of Italy on the summer/early fall can be scorching hot. And Pompeii scavi doesn't have a lot of shade.

• Trains between Salerno and Pompeii are frequent, but the station is in the main town. The Archeological park is a little less than a kilometre walk away. See the Trenitalia website for times. Each way would take about an hour (plus possible wait times)

• You can do the site yourselves, or pick up a guide at the entrance. Or hire a recommended private guide in advance. 2 hours would only give you the most superficial glimpse of some of the highlights. 4 hours would be better, obviously. We spent over 6 hours (on a cool spring day) and still didn't see everything there was to see. Most first timers fail to grasp the immense size of the site.

• You can find the ferry sailings between Salerno and Amalfi or Positano online. Be aware that sailings may be cancelled for adverse weather or sea conditions . The alternative (worst case scenario if you got stranded in Positano) would be a bus (often VERY crowded in summer) or a very expensive taxi.

-Even though the ship will be in Salerno for 12 hours, you won't have that much time to sightsee. There's no guarantee that you will be able to disembark immediately, and you'll have to be back aboard by around 6:00.

We stayed in Salerno as home base on the Amalfi in 2015. We took a day trip to Pompeii, and I feel that trip in the time frame you have is dicey. However, you can get on a ferry and tour the coast. I would suggest you get off at Amalfi and take the bus up to Ravello. It is so charming, and you can tour Villa Rufolo or Villa Cimbrose with amazing views of the coast. Salerno also has a charming old town and a lovely Lungomar (shore walk). The view of Positano from the water is gorgeous, and that is as far as I'd go on the ferry.

The ferries run frequently along the coast. If you download the travelmar app, you will have all the departure times and schedules for the ferry. I think pompeii would be pushing it a bit with only one day. The Ferry along the coast and a visit to Amalfi/Atrani would best suite your time frame. The train station to the ferry docks is only a 5 minute walk. You can purchase tickets at the docks. The cost to Amalfi from Salerno is only 8 euros each way.

Nwvp, the month of the year is very important. From May to September, this area is very crowded, and you can assume that every ferry and every bus will be full. Your getting back to the ship before it leaves without you may depend on public transportation, in a part of Italy (!) that has been starved for Infrastructure and operating government funding for generations. Do you ever use public transportation at home? In the words of Clint Eastwood, "How lucky do you feel?"

I personally would choose Pompeii, because there's only one train involved, and it's a mainline, scheduled service. But as noted, it stops far from the ancient site, in modern Pompeii city. And if some rail problem occurs, an expensive taxi is possible. (There is only one road on the Amalfi Coast, so the speed of an emergency taxi to the Salerno port from Amalfi (or up on the hill in beautiful Ravello) is not entirely under the driver's control.

Edit: An alternative is the less well known but also iconic ancient site of Paestum, by rail from Salerno. This would be less crowded, but no one will ask you, "Hey, did you see Paestum?" If you have motion sickness, I wonder if you want to take a ferry that is sometimes cancelled for rough seas?

You didn't say what month you'll be in Salerno; permit me to repeat if you're there during the high season Pompeii will be crowded and the Amalfi could be crawling with people. Last August 2017 (yes, it was super hot, and there were lots of people) we made arrangements with a private tour guide for a tour of Pompeii and Herculaneum. She was waiting when our ship arrived in Sorrento (not Salerno). We toured Pompeii and Herculaneum with an in-depth commentary on both sites and we were brought back to the ship with about an hour to spare. She watched our time closely throughout the day. It was a superb day. I suspect if you would make arrangements far enough in advance she could meet you in Salerno. As I recall if there are only two of you, the cost would be rather high; we had four people on our tour. This woman has a PhD in the history of the region and is a consummate host. She provided a driver and a Mercedes van for the day. If you're interested send me a PM and I'll provide more information. If you would take her tour it would be a full day (Amalfi would have to wait for another visit).

As has already been noted, Pompeii is very, very large, and making a DIY visit would be, in my opinion, overwhelming. Our guide methodically took us to the most historically significant places in Pompeii (and Herculaneum) and pointed out details that, when woven together in her commentary, made everything we saw make sense. If you are not interested in a guide for the Pompeii visit, I'd suggest you stay in Amalfi and enjoy your day just taking in the remarkable coastline.

Almost without exception, you would be under definite time constraints with a trip to Pompei. And if it's in high season and/or hot, I wouldn't do it anyway--you'd be asking for trouble...

...unless you had a private driver/guide picking you up immediately upon disembarking at Salerno, taking you to Pompei (1 hour drive), then 2-3 hours at the ruins where you would see the highlights but only maybe half of them--it's a huge but spectacular site. Then a driver could take you back to the port at Salerno, where with your time remaining you can walk their charming Old Town, have a great meal, then stroll their 'lungomare' and wait for the boat back to your cruise ship.

This will cost you in the hundreds of Euro but it is worth peace of mind. Public transportation in and around the Amalfi Coast up to Naples as a rule takes much longer than you would think, except from November through March.

There several towns to visit between Salerno and Amalfi. Ferry schedule below.

https://www.travelmar.it/en/hours

Pompeii would be too time consuming without a private driver.