International efforts to protect biodiversity depend on transnational collaboration and on public support for transnational policies to be implemented. Yet, we know little about what may compel citizens to support such transnational conservation efforts. In this paper, we design a lab-in-the-field experiment to explore how different framings and information about support shared across borders affect a citizen’s conservation donations. Using a dictator game, we ask for donations from individuals in Denmark, Spain, and Ghana for the protection of natural habitats of the migratory Montagu’s Harrier (Circus pygargus). We focus on citizens from Denmark, Spain and Ghana since these countries lie along the harrier’s migratory route. We found that information affects donation behavior, albeit differently in each country. Our Danish and Ghanaian participants contributed more when (1) pre-donation information stressed that transnational collaboration is needed, and (2) they were told that a measure of their group’s donation would be forwarded to other participants. In contrast, our Spanish participants donated less overall and were insensitive to the information treatments. The results document large differences across countries in supporting behavior in such transnational conservation settings and could influence how international conservation organizations organize and shape fundraising for their work.