There are a few options to stay overnight in different types of places if you are hiking or trekking in the mountains of Bulgaria:
Using the mountain huts infrastructure: This provides you with a great opportunity to spend all your time surrounded by awesome scenery, as most of the huts are high up, between 1000 and 2500 m. elevation. Multiday treks in Rila, Pirin and Balkan Mountains are possible only if you use that sort of accommodation. Most of the huts in the mountains of Bulgaria were built during the Communist time. In that period the ownership and maintenance were centralized and there was stable financing.
At present some of them are private, some – rented for a long period of time, long enough to motivate the occupiers to put money in reconstructions (if they can afford it), and some are still managed by BTS (Bulgarian Tourist Union, the old communist еrа organization with considerably lower potential today). This brings to big differences in the quality of the services. There are places that are renovated and offer good facilities and others where there is a struggle to prevent the roof from falling down. In general, in the high season (June-September), with or without reservation, you can expect to find somebody to welcome you and something to eat all around the huts on the popular routes. Lodging is usually in dormitories from 4 to 20+ people in each, inside or outside toilets, warm shower is probable.
breakfast – zakuska
dinner – vecherya
lunch – obyad
packed lunch – suh paket
shower – dush
water – voda
Camping – if you are keen to carry a tent with you, you should know that camping is prohibited in national parks, nature parks, reserves and water supplement areas, unless you stay in a camping site. There is lack of such a facilities in Rila, Pirin and Balkan mountains and very often tents are placed near the huts in summer. This may be a good idea in August and save you from the noises of a crowded dormitory but according to national park regulations even these areas are prohibited for camping, or a limited number of tents is allowed near the hut – always ask the local guardians in advance, before setting your tent! There is no problem to camp free anywhere else outside protected areas but in general, don’t expect to find any camping facilities in the mountains.