3 nights, Civitavecchia (Rome) to Barcelona

Three nights, four ports, no sea days. This is a one-way run from Rome to Barcelona, and it moves. Two of the calls are gateways that ask you to commit to one inland city and do it well. Civitavecchia is Rome's deepwater port, with the FL5 regional train reaching the capital in roughly 45 to 60 minutes; buy the BIRG day ticket so you can hop off at Ostiense for the Colosseum or San Pietro for the Vatican and ride the metro all day on one fare. Livorno is the same shape, about 90 minutes inland to Florence or 15 to 20 minutes to Pisa, so pick one and reserve your museum slots before you go. The middle call is the one I'd circle. Villefranche-sur-Mer is a tender port that lands you in the old town, a ten minute walk from a station with frequent trains to Nice and Monaco in minutes, so you control your own day instead of riding a bus tour.

Pick this sailing if you want the highlights of three countries fast and you're comfortable with long transfers on the gateway days. Skip it if you want a slow, port-forward pace or coastal towns over capital cities, because two of these four days are largely about the train ride inland. Barcelona is your disembarkation city, dense and walkable once you clear the Adossat quay shuttle.

Explora II is all-suite and all-oceanfront.