|The stage of latency – when compared to peaks of “hot mobilization” – does not necessarily refer to period of silence of dramatically limited activity. The case of The Idealists, a Czech civic association led by group of five young sympathisers of social-democratic ideology, suggests that the latency period – though it differs in intensity of use of social and mass media – may be used for building an audience and acquiring communication skills and contacts that enables certain professionalization of communication repertoire employed by the activists. The Idealists are a “progressivist and culturally liberal” civic association that has around 120 members with explicit social-democratic orientation. The active core of The Idealist consists of rather young people – the leader of the association is 26 years old and most members are young people below 30. Importantly, and unlike most other youth civic associations in the Czech Republic, The Idealists are explicitly oriented on the sphere of institutionalized politics (many members, especially the older ones, are members of the Czech Social Democratic Party). This orientation and the association’s ambition to influence critically the social-democratic politics in the country (currently perceived as being in major crisis) are accompanied by a pressure on quality and impact of the association’s public communication: The association has eventually employed a successful media strategy due to developing a qualified PR team using social media as the most important channel but reaching even to mainstream mass media. In 2017 election campaign, the leader of the Idealists became the most popular candidate of the Social Democratic Party on Facebook, having received more followers than the prime minister. However, the association members were continually active even before election, creating content presenting their ongoing projects and spreading popular foreign activist videos (with Czech subtitles) to support their causes. The presentation compares the association’s communication and use of media (both as part of internal communication within the association and as a tool for addressing public) during the latency stage and in mobilization period. The presentation draws on an ethnographic study of the association carried as part of CATCH EyoU project (Horizon 2020) in March–December 2017 and including material from observations, qualitative interviews with 8 members of the association and 46 quantitative questionnaires enabling to compare the youth association members and their political practices and attitudes with general Czech youth population (covered by representative survey in late 2016).