Schengen 180 days rolling - how to "count" ?

Technically, it’s the departure from the Schengen Zone, not the EU that is key. There are many Schengen Zone calculators that you can google that make the counting easier! Your 180 day clock will start on your arrival date, assuming you haven’t been in the Zone in the previous few months. The date of departure is also included in the calculation.

Your last day in the Schengen Zone will be 25 October as you will have been sailing in European waters which will be in the Schengen Zone.

As mentioned it is the Schengen area and not the EU that has the 90 days in 180 days rule. You don't mention any exact dates but if 25/10 is your last day in the Schengen area that is 26 Schengen days, with your earlier 65 days it makes 91 days. So you need to make sure that your two visits are far enough apart. The question you have to ask yourself is, "on the day the cruise leaves the Schengen area, in the 180 days before that, how many days have I spent in the Schengen area". Note that arrival and departure days count as full days.

And since we wouldn't have been in the EU for over a year before the
Spring.. Does our 180 end when we leave or come back in late
September? I'd really like to be able to come back a bit earlier and
spend a week or 2 in Sicily or elsewhere before the ship.

The 180 days never end and are not reset when you leave the area.

As Jennifer indicates, you have to be very careful when you go in and out of the Zone, because if you are not out for the entire day, it counts as a Schengen day. In other words, if you left the Zone on July 20 (arbitrary date selected by me) and landed in Rome on September 30, that would be 71 days outside the Zone.

I like to spend a lot of time in Europe myself. The easiest way to make this work is to include some time in a non-Schengen country. It's not a good idea to push right up to the 90-day limit in any case. Sometimes things happen. I got sick on about Day 84 back in 2015 and recovered just in time to cross the border from Slovenia to Croatia on Day 90. Since then I have planned not to exceed 88 days in the Schengen Zone (and I cross my fingers).

It is pretty simple and easy to track but some advice is complicated. Both arrival and departure days count. It is a look back situation. Take today -- Oct 13. -- Count back 180 days. What is the total number of days you have been in the Schengen zone (not EU) during those prior 180 days. If it is 90 you are done. Tomorrow you do the same thing and a month from now you do the same thing. It is always what has happened in the prior 180 days. You are always ending 180 day cycle. You are not starting a 180 day cycle. Look back, not forward.

Frank explains it quite well. The 180-day reference period is not fixed. It is a moving window, based on the approach of looking backwards at each day of the stay (be it at the moment of entry or at the day of an actual check, such as inland police control or border check upon departure). Absence for an uninterrupted period of 90 days allows for a new stay for up to 90 days. I don't see how you get to do the cruise and the extra time in Sicily as described without overstaying. You may want to consider returning home in late June so have 90 days out of the zone so you have the ability to do the second trip as planned. Or maybe apply for a long stay visa at your first point of entry or maybe spend some weeks of the time in Europe for the earlier trip in non-Schengen countries like for example Croatia, Ireland, Turkey, and the UK. A way to look at it is to use October 25th as your departure date and a date when your passport will be checked, looking back from there 180 days, you get to April 29th so during the period from April 29th to October 25th, you can spend 90 days in the Schengen Zone.

Thank you all so much!
I think I have it. I like the "count back 180" process. That makes sense to my befuddled brain.

I had wanted to do @ a month in Portugal, couple of weeks in Provence (for lavender) and meet family in Greece @ June 24 for a 2 week period with them. That bit is the only fixed period - due to the teen's school dates.

Think I will probably drop Provence and do it in '22... OH shucks - I'll have to plan another trip ! But wait - then we can do more of southern France.. Yippee!!

Try to avoid visiting southern France in mid-summer. It gets quite hot at that time of year.

Here's a Schengen calculator site that might be helpful:
https://schengen-calculator.com/

Thank you Kathy H. (hope you are also enjoying our slightly cooler temps)
Works like a dream and pretty easily. I'll be certain to bookmark that site.
I can see where this would make life way easy for someone who frequently traveled to and from. Wish the country names were alphabetical.

By it's allowing me to not count sea days and the 4 non-schengen ports - gave me an "extra" 11 days..

I'm thinking we won't cut it that close - But made me so much more comfortable with the updated plans I'm making.

Thanks to all for the help and input. Happy travels!

careful about taking advantage of those sea days. You won't get entry and exit stamps (or virtual stamps, electronic notes) so you will need to have good records about dates and times.

Also, if arrival and departure ports are Schengen then you will not have left the Schengen zone and you will count those days. Only when you clearly go to a non-Schengen port can you not count.

Cruises often cruise at night. Schengen days start and end at midnight. If any part - even a minute - of a day is in the Schengen zone you need to count it - the authorities will.

I had trouble understanding the rolling nature of the 180 days, in fact, I didn't understand that rolling occurred. Please see this old thread, in which so many were so patient with me. https://community.ricksteves.com/travel-forum/general-europe/schengen-clarification-please

We took transatlantic cruises both ways. As I could find no conclusive answer anywhere about how to count cruise timings, including from a consulate when we tried for a visa, I counted them as "IN". So our first day in the Schengen zone was the day we stopped in Ponta Delgada, heading westward in April. I never knew if that was necessary, but I didn't want to find out the hard way that it indeed was. I counted it again as the last day on our return voyage in November. I counted forward, backward, and sometimes it seemed from the middle. I did it with paper and pencil. I think I did it in my sleep! The calculator suggested by Kathy H contains this page, which is a wonderfully easy to use worksheet: https://schengen-calculator.com/visits I did print a copy of that just in case. Yes, anal! We spent our "OUT" time in Britain, a bit over 90 days. That part would be similar to your returning home between your two trips. As we progressed through our trip, passing the 180 days mark, those early "IN" days began to fall off, allowing us more.

Happy counting!

Donna

We've had a report or two of people missing flights, or observing others missing flights, because of real or suspected perceived Schengen Zone timing issues. That can be very costly.