This study investigates the socio-economic effects of Illegal, Unreported and Unregulated fishing (IUU-fishing) on households of small scale fishermen, whose income derives almost entirely from fishing. The research question is ?What are the socio-economic impacts of IUU-fishing and government?s countermeasures on Thai fishing communities, in particular small scale fishermen?s households, before and after 2015??. A mixed quantitative and qualitative approach was chosen to better grasp the complexity of fishing-related changes to household income and by the case study of a small scale fishing community in Ao Noi Subdistrict of Prachuap Kiri Khan Province. This resulted to a general understanding of the extent to which the community members were aware of IUU issues, as well as in their participation in related governance processes. The main results show that the small scale fishermen were impacted by those who perform IUU-fishing. Since the enforcement of the new regulation in 2014/2015, the fishermen have felt some improvement through the regrowth of fish stock and the enforcement of stricter regulation for commercial vessels. The income situation has, after initial gains, seen some losses in 2016, mainly due to higher costs or investments. The results shall provide a set of data for future research on the socio-economic situation of small scale fishermen. This approach might be useful as a template to be applied to other small scale fishing communities in Thailand or elsewhere. The limits of this work are clearly given by the sample size and the selected target community.