There has been increased interest over the last decades on community based management of natural resources (CBMNR) and their relation to environmental sustainability. Insufficient studies dedicated in Kenya to understand pastoral communities’ management is striking, considering the importance of communal management for pastoralism and of pastoralism in Kenya. This research has been set up to conduct a study of customary management of relatively well functioning pastoral commons of East Africa, the Mwanda-Marungu commons which borders Tsavo west national park in Taita hills, south-west of Kenya. Through ethnographic approaches such as participant observation, semi-structured interviews and focus group with discussions of up to 234 respondents, it was examined whether customary management systems of Mwanda-Marungu would offer sustainable model that conforms to the IUCN’s Other Effective area-based Conservation Measures (OECMs) and where not, as well as why and which were the sources of possible malfunctioning. Among others the results showed that these pastoral commons assure a generalized local rule requiring that all herders and livestock should have left water points and salt lick areas by 3pm so as to pave way for the wildlife to drink water and lick salt as well in order to avoid illnesses transmission and favoring humans-wildlife co-existence within the commons. Also there are important restrictions on charcoal burning and fires within commons as well as the use of religious shrines called fighis that all together help to conserve forests and pastoral habitats, which are absent in other areas where private plot selling and mining has started to come in and degradation is much stronger. This study demonstrates that pastoral communities in this area have devised ingenious measures that prove good management of natural resources within their commons aligned to the principals of OECMs and they could be considered for support, since where they disappear environmental degradation tends to appear.