In recent years the country has become a key transit route after EU countries closed their borders to new arrivals
Hundreds of migrants, including Bangladeshis, hoping to reach the European Union are sheltering in forests and ruined former factory buildings near Bosnia's border with Croatia, with the cold setting in and conditions becoming more miserable.
On a cold Wednesday morning, migrants from Bangladesh, Pakistan, Morocco and Algiers shivered in their makeshift tent camp high in the woods above the town of Velika Kladusa, built of cardboard and tree branches and covered with nylon sheets.
Some set up fires to warm up and cook modest meals. Others washed themselves and their clothes in a freezing forest stream, and brushed their teeth with ashes.
As the EU attempts to overhaul its defunct migration policies, thousands of people fleeing Asia, the Middle East and Africa are stranded on the fringe of the wealthy bloc, trying and often failing to enter and continue their journey.
Migrants and refugees mostly bypassed impoverished Bosnia during their mass movements across the Balkans in 2015-2016, but in recent years the country has become a key transit route after EU countries closed their borders to new arrivals.
"[There are] many problems here," said Mahmood Abal from Bangladesh. "No rooms, no water, no medical facilities, no sanitation."
He is one of about 500 men who were turned away from the Bosnian towns of Bihac and Velika Kladusa. Authorities are refusing to host large groups of migrants any longer and are preparing to close down some reception centres.
Sympathetic at first to the plight of the migrants, similar to their own during the war in the 1990s when they were forced to flee, Bosnians in the Krajina border region have become anxious, demanding that other regions share the burden.
But in ethnically-divided Bosnia, the Serb and Croat-dominated regions refuse to accept migrants, and so they concentrate in the Bosniak-dominated Sarajevo and Krajina.
Most migrants are smuggled to Bosnia in rubber boats over the Drina River, the natural border with Serbia, said Azur Sljivic, a Bosnian border police officer.
"Many of them drown because the Drina River is unpredictable, full of whirlpools," Sljivic told Reuters while patrolling along the border in the eastern town of Zvornik.
Yet they do not give up.
On Tuesday night, about 50 migrants left their Bosnian forest tents to try cross the Croatian border.
"Italy, see you soon!", one of them shouted cheerfully.