With the nightmare of inter-ethnic war behind it, the Balkans are no longer the forbidding place they once were. Most countries get along, at least nominally, and travel between them is largely hassle-free.
There are still some hot points that while not dangerous, can present unpleasant surprises to the unprepared explorer.
When travelling through the Balkans, there is really one holy rule to follow: if you want to visit Serbia and Kosovo, start with Serbia.
As the big dog of the region, Serbia hasn't recognized Kosovo's 2008 declaration of independence. It still sees Kosovo as one of its provinces. Therefore, it doesn't recognize a Kosovo visa.
(Things got really heated before the 2008 declaration of - unrecognised - independence)
If you must go from Kosovo to Serbia, you must arrange to get a Serbian visa beforehand. If you try to cross the checkpoint with only a Kosovo visa, you'll be deemed to have entered the country illegally.
If want go into Kosovo and back to Serbia, be aware that your Serbian visa (or entry stamp, usually valid for 90 days) will still be counting in your trip to Kosovo. If you stay past the deadline, you could be charged with overstaying.
But many a traveller has reported crossing with minimal hassle. Serbian guards, they say, might simply cross out the Kosovo visa and stick a Serbian one on top.
Others have simply been turned away. Save yourself the risk. If you must go from Kosovo to Serbia, go through Macedonia.
All other borders are open, with new roads being built regularly between formerly belligerent nations. For instance, there's a nice new highway between Albania and Kosovo, replacing a harrowing, 10-hour mountain ride. (The picture accompanying this article was taken in this region - gorgeous eh?)
One border crossing, between Rastelica in Kosovo and Strezimir in Macedonia is, officially, for locals only. I's only open from May through September due to weather.
Summer traffic between both nations can be hectic, and you might wait hours to cross. Consider going through Bosnia-Herzegovina instead. There's a catch: you might have to pay a 20-euro Green Card for Bosnia.
Most border crossings are only open until 10 pm.
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