It could have been a normal summer’s day in Southampton, Britain’s busiest cruise port. Five big ships were checking in, including P&O Cruises’ shiny new Iona, with a capacity of 5,200, about to embark on its maiden voyage.

What wasn’t normal, though, was the presence of the drive-through Covid testing centre. Carnival Corporation has its own centre, which Iona was sharing with Regal Princess that day. While the process was efficient once you got to the front of the queue, I’d say it added 90 minutes to my check-in time.

All five ships were on round-Britain cruises, which restarted in May. I’ve been on three of these now (MSC Virtuosa, Celebrity Silhouette and Iona), as well as two in Greece, with Variety Cruises and Silversea.  What’s struck me is how every line interprets the Covid protocols differently.

Iona is a beautiful ship, with more than 30 bars and restaurants and fantastic live music in the evenings. But because of social distancing rules, venues are running at reduced capacity and you’ve got to be organised to do what you want.

By the middle of the seven-day cruise, all the speciality restaurants were fully booked. I found some of the changes strange, too. Evening turn-down service has gone “because of the protocols”, according to my cabin steward. Why? The cabin can be cleaned in the morning, when I’m not there, so why not in the evening?

On Silversea’s new Silver Moon, which has been sailing out of Athens since July, COVID protocols are handled with panache. Everybody is tested before boarding and again, at no cost, towards the end of the cruise.  Your Fit to Fly certificate, required by some governments for passengers returning home, is returned with your passport.

In addition to the array of goodies in my suite – Bulgari shower gel and shampoo, champagne, fruit, chocolates – there was a smart Bulgari clutch containing masks, little bottles of hand sanitiser and sanitising wipes. As well as bringing ice and slices of lime for my evening G&T, my butler very politely took my temperature every morning.

We had to wear masks on board, which all of us in Europe are completely used to by now, but some found it cramped their style somewhat. “The crew are wonderful but it’s not quite the same,” one regular solo traveller told me, wistfully. “It’s harder to get chatting to people wearing a mask. And you can’t sit at the bar and meet people, only at the tables.”

Greece, where the vast majority of ships are sailing this summer, is having something of a rollercoaster ride, thanks to snap lockdowns as COVID cases rise in tourist hotspots. I spent a week on Variety Cruises’ tiny Harmony G, sailing almost full with 40 passengers. Variety offers half board cruises, so most evenings, you’re ashore for dinner, making it easier to gauge the mood on the ground.

Mykonos went into lockdown the day we were there, with a 1am curfew and all clubs closed, so Chora, the pretty capital, was subdued, with no music allowed in the bars. This doesn’t affect cruise passengers, who leave in the evening, but it’s a sobering reminder that COVID is out, there, invisible and menacing.

Santorini was packed –  so much so that I wore my mask to squeeze through Instagrammers packing out the narrow streets of Oia. And yet we had the archaeological site of Akrotiri to ourselves.

We spent a morning anchored off Delos, where I wandered around the ruins of 2,000 year-old houses and temples with only cats for company, insects humming on the still air. We swam off the back of the ship in deep, clear water. We sat in the leafy square of Kapsali, Kythira’s pretty hilltop town, enjoying morning coffee without a care in the world.

Yes, the euphoria faded a little as I queued nervously at Athens for my flight home armed with vaccination certificate, Fit to Fly test and the insanely complex Passenger Locator Form required by the British government. Get this wrong and you can’t board the flight.

But it was worth it. Despite the new complexities, it feels so good to be travelling again.