Noticed you posted this query on one of the S9 threads too, but I'll answer you here.
All Samsung smartphones come with a regional lock out of the box. This lock disappears after at least five minutes of total talktime using a SIM from the phone's region of origin (in this case EU). This should, in theory, allow you to use the phone in other regions - but network services can vary, so if you're after a specific network overseas it's best to check with their customer services.
Apps and services (e.g. Samsung Pay) can vary between countries too.
We've had a similar S10 thread here, if you want to check out what other users have advised too.
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