Bulgarian Federation of Speleologists (BFS), 1140 Sofia, bul. Levski 75 tel & fax 02/987 8812. Umbrella organization for local caving groups throughout Bulgaria.

Odysseia-in , 1000 Sofia, bul. Stamboliiski 20 tel 02/989 0538, fax 980 3200, . Bulgaria's leading adventure tourism agency, offering all kinds of individual and group tours. Its shop, Stenata (ul. Tsar Boris I 117), sells camping and climbing equipment, and rents out mountain bikes.

Pandion , 1407 Sofia, ul. Cherni Vrâh 20A (tel 02/963 0436, ). Offers all-inclusive trips with a bird watching theme.

SunShine Tours , 1111 Sofia, ul. Shipchenski prohod 47 tel 02/971 3628, fax 973 3048, sunshine@techno-link.com . Wildlife, hiking, cultural heritage and archeological study tours, tailor-made for groups and individuals.