This paper represents the annual report of a multi-Member longline survey on Antarctic toothfish (Dissostichus mawsoni) at Subarea 48.6 in the 2017/18 fishing season by Japan and South Africa. The data set, C2 and Observer data, was provided by the CCAMLR Secretariat on the 3th August, 2018. In this paper, the data set during current fishing season (2017/18) was used for reporting the quantity of data, samples collected, and results of quick analysis as a progress toward research millstones. The research operations at Subarea 48.6 have not yet been completed in the 2017/18 fishing season. Also, some data is not reflected in tables and figures because it is still under process.