The study of turnout of expatriates has aroused early attention in the literature on external voting, given the low generalized participation rates. Although some causes have already been considered, not much progress has been made in theoretically supporting these reasons. At the same time, most are case studies or comparisons between a few cases, with mostly descriptive analysis strategies which do not allow to make causal inferences. In addition, the very few studies of large N cover short periods of time or do not address electoral participation. So, which are the factors that condition emigrants' turnout is a question that still needs to be answered. Drawing on an original data set of 104 elections held between 1990 and 2017 across 15 countries of LA and based on rational choice theory, we compare turnout at the aggregate level seeking to explain its variation among countries and over time, using time series and fixed effects models. The results show that turnout increases with simplified registration procedures, flexible deadlines and in presidential and second-round elections. Likewise, polarization contexts and majority electoral systems reduce the dissuasive effect on participation of non-competitive elections.