99% certain port days count, given anyone cruising has to have all the appropriate documents to enter said countries, just like if flying into the country, etc. And the cruise line provides a manifest, immigration clearance is done in masse for those who don't need a visa, those who do need a visa have to do a face to face meet, etc.

So yeah - you're entering the country, even if it's just one day (or 3 days, in your cruise case) - they'd count against the count, so to speak...

I think they days count as well. Can you shorten your 88 day visit by a couple?

Sea days travelling between Schengen countries also count.

The cruise is considered the transport rather than an island of sovereignty.

You’ll need an electronic visa for EU and UK depending upon when you are coming over and that’s if not working etc., just clarifying as that’s a long stay and you’ll be asked to prove your means at the border. So in short every day you are in the EU or Schengen counts toward the cumulative days of stay maxed at ninety during the prescribed prior period. You’ll gain a day or so waiting upon departure by ship from Britain.

Bear in mind nomad / remote working may be considered as employment whilst within the region. Just chucking that up there….

According to the EU, as quoted in this article, sea days transiting from one Schengen state to another, count towards your 90 day limit.

https://www.theolivepress.es/spain-news/2024/02/01/will-a-cruise-holiday-in-europe-count-towards-my-90-day-schengen-limit-how-some-brits-are-avoiding-the-post-brexit-travel-rule-amid-utter-confusion-among-eu-and-uk-authorities/#:~:text=%E2%80%9CAs%20a%20general%20rule%2C%20calls,be%20registered%20by%20the%20authorities.%E2%80%9D

How are they going to know though when no one checks your passport at any of the ports i've visited in the EU / Schengen?

Steve just because you do not show your passport the ship submits a passenger list to the authorities before the ship arrives in port for clearance

Addressed in #2.

Manifests are submitted to each port in advance, most immigration is done as a bulk check, but some nationalities do have face to face (us, for instance, lol). Last sailing from Southampton to Schengen, yup - first stop was Belgium and there was hubs, bright and early at 5:30am for immigration check, then back in the cabin for another couple hours of sleep before we headed out. 😆

Just cuz you may not see it happening, doesn't mean the officials are officiating.