21-DAY MEDITERRANEAN & GREEK ISLES: ISTANBUL OVERNIGHT

Barcelona is where more Mediterranean itineraries start and end than anywhere else, which means that for most people it is the day before or the day after the cruise rather than a port day.

Treat it as a city break, not a call. Coming in a day early is the single best decision available on a Mediterranean itinerary. It absorbs a delayed flight, and it turns Barcelona from a taxi ride into two of the better days of the vacation.

Book the Sagrada Família before you book anything else. Timed entry, sells out weeks ahead in season, and it is not remotely the same building from the outside. Park Güell is also timed now and also sells out.

The cruise terminal is not walking distance. The Adossat quay is about two miles out along the mole. The blue Portbus shuttle drops at the Columbus monument at the bottom of the Ramblas; taxis are metered and cheap.

Pickpockets are a genuine, organized problem on the Ramblas, in the metro and around Sagrada Família, not dangerous, but professional. A zipped bag in front of you handles it.

Eat late. Lunch is at two and dinner starts at nine. A restaurant serving dinner at six thirty is a restaurant for people off ships.

Every itinerary that says “Rome” means Civitavecchia, and the distance between the two is the entire planning problem of the day. The port is about fifty miles up the coast. Door to door (ship, shuttle, station, train, metro), you are looking at ninety minutes to two hours each way.

Pick one thing in Rome. With a twelve-hour call you get roughly six hours in the city. That is the Colosseum and the Forum, or the Vatican, or the centro storico on foot. Trying for two of the three is how people end up seeing lines.

Book skip-the-line entry in advance for whichever you pick. The Vatican Museums and the Colosseum both run timed entry and both sell out; a walk-up in July is a two-hour line in full sun.

The train is cheaper and often faster than a bus, but it is also the thing that strands people. Ship’s excursions have the ship’s guarantee behind them; a regional train does not, and Italian rail strikes are announced days ahead but are not rare. Check before you commit to going independently.

There is a real alternative to Rome. Cerveteri, twenty minutes down the coast, is a UNESCO Etruscan necropolis of round tombs cut into tufa that you walk down into. Tarquinia, the same distance the other way, has the painted tombs. Both are extraordinary, both are twenty minutes from the ship, and on a day when four ships are in you will have them to yourself.