Cross-Border Car Rental from Tivat Airport. Picking up at Tivat Airport (TIV) and crossing into Croatia, Bosnia, Albania or Kosovo — the most important thing happens before you leave the airport lot: get WRITTEN cross-border authorization added to the contract at the desk, and make sure the ORIGINAL vehicle registration is in the glovebox, not a photocopy. The airport handover checklist: (1) written authorization naming the allowed countries — adding a country mid-rental can cost about €50 admin (AbbyCar); (2) book with notice — some suppliers need cross-border permission requested days ahead; (3) check the glovebox for the ORIGINAL registration (copies/scans/photos are rejected — the #1 turn-back reason); (4) airport desks charge higher cross-border fees than city offices. Do you legally need a Green Card? Not for Croatia, Bosnia or Serbia — Montenegro is in the Multilateral Agreement License-Plate Subsystem, so the plate proves insurance; the cross-border fee is a commercial surcharge, not a border tax. Green Card is mandatory only for Albania (buyable at Bozaj about €15/14 days). Kosovo is outside the Green Card system (border TPL about €15/15 days; often banned). Tivat to Croatia is about 72 km / 2h via the Lepetane-Kamenari ferry (€5 flat per car, every 10-15 min in summer) then Debeli Brijeg (Jul-Aug queues 2-5 hours; Vitaljina passenger-only bypass 24/7). Tivat to Bosnia (Trebinje) is about 55 km / 1h20 via the ferry and the Sitnica / Zupci joint border post (since April 2025). Cross-border fees by company (indicative, Summer 2024, verify at the desk): Europcar Montenegro €6.05/day capped at €60.50 (Kosovo/Greece/Bulgaria/Romania not allowed); Sixt €40 flat (Kosovo not included); MTL Rent €50 flat plus a 200 km/day limit, €0.10/km over; CarWiz €50 flat; Stella Car €25 flat (Kosovo banned). GPS geofencing flags unauthorized crossings — insurance void plus AbbyCar €500 penalty. Serbia has a strict 0.03% alcohol limit and needs a vignette; winter tyres 15 Nov-1 Apr, minimum 4.0 mm tread.