Cross-Border Car Rental from Ulcinj. Ulcinj is Montenegro's southern outpost — the closest town to Albania and the natural gateway to Albania and Kosovo; most Ulcinj renters heading across a border go south into Albania, not north into Croatia. Ulcinj to Albania: Shkoder is about 26-40 km / 30-50 min via the Sukobin / Muriqan crossing, a single joint checkpoint (both countries in one facility, roughly halving processing), 24/7 with peak queues up to about 2 hours. Albania is the one border where a Green Card is LEGALLY required, and it is NOT sold at Sukobin — arrange it through your rental company before leaving Ulcinj (Bozaj sells it about €15/14 days but that is not your route). The Green Card myth for the other borders: for Croatia, Bosnia and Serbia a Green Card is NOT legally required — Montenegro is in the Multilateral Agreement License-Plate Subsystem, so the plate proves insurance; any Green Card fee for those routes is a commercial surcharge, not a border requirement. Kosovo from Ulcinj — the payload trap: Kosovo is outside the Green Card system, so you buy border third-party insurance from the Kosovo Insurance Bureau at the crossing. For a normal passenger car it is about €15 for 15 days, but if the rental is a large SUV or pickup with a payload over one tonne it jumps to about €138. The Kula / Kulina crossing runs only 06:00-22:00 (not 24/7, winter closures possible), and many companies (Europcar, Stella Car) ban Kosovo outright. Documents at every crossing: the ORIGINAL vehicle registration (copies rejected), rental agreement plus written cross-border authorization, a passport (EES biometric checks on the Croatian/Schengen side), and a paper Green Card for Albania. Croatia and Bosnia are the long way from Ulcinj (Croatia about 185 km), best treated as a planned multi-day leg. Cross-border fees by company (indicative, Summer 2024, verify): 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). Never let GPS route you across an unauthorized border — AbbyCar charges €500 plus voids insurance. Serbia has a strict 0.03% alcohol limit and needs a vignette; winter tyres 15 Nov-1 Apr on the mountain route to Kosovo, minimum 4.0 mm tread.