Several decades of experimentation have found that âGet-Out-the-Voteâ (GOTV) campaigns can effectively increase voter turnout. Yet, little has been said about the ability of similar-style campaigns to encourage participation in other types of civic engagement, such as citizensâ assemblies, which require much higher levels of commitment. Furthermore, although studies have found general support for citizensâ assemblies, willingness to participate is higher amongst those already more politically engaged and with higher levels of education, presenting a challenge to claims surrounding legitimacy and representation. In this article, we conduct a GOTV-style field experiment, complemented by a doorstep survey, to increase and understand perspectives towards registration for the 2023 Southampton Citizensâ Climate Assembly. We find that canvassing can be an effective method for increasing registration, including from under-represented groups. However, there are considerable barriers to participation, particularly the level of commitment, personal interest, and concerns about impact, which limit recruitment efforts.