Political discussion networks significantly influence citizens’ political behaviours and attitudes. They promote political information and facilitate mobilisation and conformity to social norms (Fowler, 2005; Huckfeldt and Sprague, 1995). It has been suggested that ethnicity plays an important role in shaping the composition and impact of these networks (Leighley and Matsubayashi, 2009). In this paper, we employ discussion network data to contribute to this debate and explore the relationship between co-ethnic discussants and their political characteristics, which we refer to as mobilisation value; how these relationships vary across ethnic minority/majority groups; and the implication of these phenomena for voter turnout in Britain. We find that, for White British, co-ethnic discussants have greater mobilisation value. However, overall, for Asians and other ethnic groups have higher mobilization value than White British or Black respondents. In turn the mobilization value of discussants has a positive effect on turnout regardless of a citizen’s own ethnicity.