I've gotten off a cruise ship in Civitavecchia four times to visit Rome. I've never missed the ship. Neither has anyone I know.

But I came close once. It wasn't in Rome, though; it was in La Spezia. And it wasn't because I went off on my own. Quite the opposite: we were on one of the cruise line's excursions.

In this post I'll tell you what really happens if you miss the ship, how much buffer I like to leave, whether it's risky to do Rome on your own, when I'd pick the ship's excursion, what I always carry on a port day, and how I make sure nobody gets left behind when I'm with a group.

The ship leaves without you. From then on, it's up to you to get to the next port on your own.

But there are two things many people don't know.

First: if you see you're not going to make it, contact the ship as soon as possible. There's always an emergency number available. Call it the moment you know you're running late, not when you're already pulling up to the port.

Second: if the ship delays its departure because of you, you pay the extra costs. A ship leaving port late racks up expenses, and the cruise line can pass them on to you.

So the key isn't knowing what to do if you miss it. It's planning your day so it never happens.

The only time I've come close to missing a ship was in La Spezia.

We were on an excursion run by the cruise line. Everything was going fine until, on the way back, we hit a traffic jam. Time kept passing, the bus wasn't moving and the all-aboard time was getting closer.

We got back late. But the ship waited for us.

It waited for one very specific reason: it was the cruise line's own excursion. When you're on a ship excursion and the delay is caused by the excursion itself, the ship waits. If we'd been on our own and hit that same traffic jam, it would have been a very different story.

That day taught me a lesson I still follow: on a port day, what's most likely to let me down isn't the train, it's the road. And leaving a buffer isn't paranoia. It's your insurance.

Here's how I plan it:

If the ship docks far from what I want to see, with a 30- to 60-minute trip each way, I plan to be back at the port with a two-hour buffer.

If the ship docks right in the city, one hour is enough.

It might sound like a lot. But that buffer does two things for me. First, it covers anything unexpected: a delay, a traffic jam, a train that doesn't show up. Second, it lets me change plans if I feel like it: linger in a square, pop into somewhere I hadn't planned or sit down for lunch without rushing.

And one important detail: count your buffer from the all-aboard time the ship gives you, not from the departure time.

For me, the risk is low. Here's why.

The train between Civitavecchia and Rome takes 35 to 50 minutes, depending on which one you take. On my four stops, I've never had a train delay of more than 10 minutes.

Plus, Rome is a huge city with lots of trains. If one fails, they usually sort it out quickly with another train or an alternative. You won't be stranded.

Where I have seen problems is on the road. So if you're doing Rome on your own, the train is the safest option, in my opinion.

It depends on two things: distance and how much time you have ashore.

My rule is this. If the trip from the ship to the place you want to visit takes more than 40 minutes, or it's short but so is your time in port, I wouldn't push my luck. That's where the ship's excursion has a clear advantage: if there's a delay, the ship waits for you. It happened to me in La Spezia.

Rome sits right at the limit, with that 35- to 50-minute train ride. But for everything I've told you, I see the risk as lower: frequent trains, few delays and alternatives if something goes wrong.

And there's another reassuring factor. The ports that usually come after Rome on Mediterranean cruises are Naples, Livorno or La Spezia, and Genoa. All of them are easy to reach from Rome by train or bus, and inexpensive too. If the worst happened, it wouldn't be a disaster.

First, don't wait until the last minute. As soon as you see you won't make it, call the ship's emergency number and let them know.

Second, check the next port and how to get there. From Rome, you'll usually have a train or bus to Naples, Livorno, La Spezia or Genoa.

Third, have what you need to get around on your own: a charged phone, cash, cards and ID. Which brings me to the next point.

This is my onshore survival kit:

These days you could buy almost all of it in a shop if you forget something. But two things can't fail: your phone and your wallet, with cash, cards and ID. With those, whatever happens, you can sort it out.

When I've gotten off in Rome with groups of 20 or 30 people, we've organized it with a WhatsApp group and shared locations. That way everyone knows where the others are and we can update each other on any changes.

But I'm very clear about this: we're all adults. Everyone looks out for themselves and for anyone in their care, like kids. I can show the route and share what I know, but I'm not responsible for making sure each person gets back on time. That's on each of us.

The whole Rome route, with train times, all 12 stops and the buffer to get back stress-free, is in my free guide.

Download the Rome Guide here

Four stops in Rome and not a single scare. The only one I've had was in La Spezia, stuck on a bus in traffic, watching the clock. Since then I always leave a buffer. And I promise you, I enjoy the day so much more knowing that, whatever happens, I'll make it back.

Have you ever had a "we're not going to make it" moment on a port day?

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