This paper examines the intergenerational mobility trajectory (class) effects on social connection and, through this, on subjective well-being in contemporary UK society. Drawing on data from the United Kingdom Household Longitudinal Study, we measured four types of formal and informal social network (civic engagement, neighbourhood cohesion, diversity and size of social networks) and used three indictors for well-being. We find that social network does play a significant role on well-being but the impact is much smaller than that of class. We also find that class is more closely related to the formal than the informal domains of social network. Demographic attributes show some influences but social network, employment, and prior levels of well-being in particular, have more salient effects on well-being. Over and above all this, class as an indicator of cumulative advantages and disadvantages has a persistent and systematic influence. Overall, the analysis shows that while enriching social connection would contribute to well-being, reducing class-based inequality is of greater importance.