Pompeii now wants your name and a time slot
Since November 2024 every Pompeii ticket is nominative - printed with the holder's name - and you show ID or a passport when you buy it. The park caps admissions at 20,000 a day. From mid-March to mid-October that cap is split: 15,000 entries between 9am and 1pm and only 5,000 from 1pm to 5:30pm.
For a cruise day this matters more than it sounds. A morning slot is the one everyone wants, and if you head out independently after a late breakfast you can find the morning allocation gone. Buy online before the trip, in the name of each person going, and carry the passport that matches.
The train to the ruins, and the fast one that stopped
Independent trips go on the Circumvesuviana from Naples Porta Nolana to Pompei Scavi - Villa dei Misteri, the station at the site entrance. Regular trains run roughly every 30 minutes from early morning until about 10pm.
The Campania Express, the tourist service with reserved seats and air conditioning that stopped at Ercolano and Pompeii on its way to Sorrento, is suspended from October 1, 2026. Check whether it is back for your season before planning around it; if not, the regular train is the option.
Sources: pompeiisites.org, positano.com