Montenegro is not in the EU, and an EU SIM charges its non-EU rate here.
Roam-like-at-home ends at the Croatian border. The Western Balkan operators and the EU have agreed a cap on roaming data prices rather than free roaming, and talks on extending the EU scheme to the region only opened in 2026 — until that is in force, a package is the simpler answer for a week on the bay.


