Matajur probably pleases everyone. The top is relatively easily accessible and the descent is long up to 10km finishing way down in Špeter village in Italy. Yes, the Soča Valley offers some amazing transboundary trails which take you across Slovenian border to the Italian side. Since there are no actual borders any more it feels very natural to explore all the area in our surroundings. Here is a Matajur South trail form the Soča Valley Guide Book in German language - PDF .
Mountain bike trails in the Soca Valley, Slovenia.