To complement @Doc answer which is spot on
Croatia is actually in a transitional period to fully abolish internal border controls
Since Jan. 1st, internal border controls are indeed abolished for land and sea crossings
For internal air controls (Croatian Accession decision)
As regards checks on persons at internal air borders, they shall be lifted from 26 March 2023 and the provisions referred to in paragraph 1, to the extent that they
regulate the abolition of checks on persons at internal air borders, shall apply as of that date
This has been done to make the change along with the switch to airlines’ summer calendar, to both give them, and the airports, time to prepare, to not disturb their operations right away and to pack all the big changes into a single timeframe
So, until March 26, 2023, all flights to Croatia leave and arrive in the non-Schengen area of the airports, as they always did previously.
Everyone will pass, on departure, exit and, on arrival, entry immigration, and have the same treatment if you are required to be stamped on Schengen area entry/exit
From March 26th onwards, all flights will now leave and arrive in the Schengen area of the airports, which will exempt you from immigration controls, the same way you could go to any other Schengen-member state.
Technically, this is probably a duplicate of this question. However, the specifics make it worthy of a new answer. As that answer states, the double parallel lines indicates that the exit from the Schengen region has been cancelled.
So, why did they do that?
As of January 1st, 2023, Croatia is a part of the Schengen Area, which in a simplistic sense means that there should be no immigration checks between those countries. When travelling between two Schengen countries, it is much like a domestic flight between two states in the same country.
Seemingly, for some reason likely related to this change being very new, you passed through immigration when leaving Sweden, and you were given an exit stamp stating you were leaving the Schengen region on that date.
When you passed through immigration in Croatia, rather than giving you a new entry stamp for the Schengen region, they instead "cancelled" your exit that occurred in Sweden. Thus, you never left the Schengen region leaving Sweden, so there is now no need to give you a stamp to say you entered it in Croatia.
At this point you are physically in the Schengen region, you have a valid entry stamp (from when you originally entered it in/on your way to Sweden), and no exit stamp (by virtue of the one you received being cancelled). I.e., you are in a perfectly valid situation, and there is absolutely nothing to worry about!
Credit:stackoverflow.com‘
4 Mar, 2024
5 Mar, 2024