The fact that online protests and offline protests are undertaken in different spaces -in the virtual space of the internet and in the physical spaces of the street- does not mean that the two are completely distinct. Indeed, they are both related to the broader context of participatory opportunities and constraints that are a function of state repression in non-democratic societies. This study examines how the dynamics of state repression shape the spaces of possible public activism, and influence individuals’ motives to participate in online protests, offline protests or both. In the heat of the Iran’s Green Movement in 2009, the striking share of mobilization attempts and protests were undertaken in physical spaces, and the internet was employed by the dissidents to support offline events. However, when activism in the physical spaces was severely repressed and the cycle of public street protests declined, offline protest and mobilization activities were gradually transferred to online space and converted to online activities. Dissidents found the internet to be not only a safe haven of communication, but a new space in which to forge their values and beliefs (ideology), establish shared identities through new social ties (networks), and calculate the cost and benefits of protest and group/individual action (efficacy). In fact, the form and amount of activities on the internet has been changed by the level of offline state repression: offline activity was not simply transferred online; online activity created a new online space, including expanding across national borders and geographical locations. Based on the unique data from three waves of online surveys and a number of qualitative interviews with online activists, this study compares the changes in the online activities undertaken by dissidents, dissidents’ participation motives, and perceived repression. The findings enhance our knowledge about the use of online space to influence politics under circumstances of severe repression, and the possibilities for continuing expansion of spaces of political participation even when the state exerts prohibitive control of offline physical spaces and opportunities.