Tropical peatlands hold 15-19% of global peat carbon with Indonesia as the largest contributor in Southeast Asia. Many of Indonesia's peatlands are degraded into fire-prone and non-forest vegetation state. There are several peatland restoration projects now being carried out by several entities with public and private investments. These projects vary in their stated restoration goals, planned activities and plan durations. Although these projects face serious social, economic and ecological challenges, the majority of the projects (3 out of 4) are being planned for the short term (5 to 30 years). Meanwhile, the time required for peatland restoration varies from decades to hundreds of years depending on the damage level. Thus, finding ways to sustain restoration efforts beyond the project duration is critical to restoration success. Little is known about how different types of actors manage their restoration projects and how much it would cost to restore degraded tropical peatlands. These aspects have rarely been studied; they are the focus of this study. This study presents a close examination of four tropical peatland restoration projects in Central Kalimantan, Indonesia, which are initiated and managed by: 1) a non-governmental organization (NGO) partnered with a national park, 2) a government agency partnered with a NGO, 3) a private company partnered with a NGO, and 4) a private company partnered with a university. We interviewed 47 key informants who are involved in these projects and also conducted an online survey to understand costs of peatland restoration projects. In the first study, we assessed how different project actors defined the concept of ecological restoration, how their definitions were being articulated into restoration goals, plan duration, and restoration activities. Ecological restoration of peatlands in Indonesia is being defined with emphases on ecological (i.e. restoring and maintaining water balance of peat) and socio-economic dimensions. Both of these aspects are influenced by their socio-ecological context and the challenges they faced in restoring degraded peatlands. In the second study, we focused on examining different socio-economic and ecological challenges that the project actors faced and how they affected costs of restoration. We built a cost-accounting framework for both direct (i.e. costs of restoration activities) and indirect costs (i.e. costs to address the socio-economic and ecological challenges) of restoration. We found that indirect costs are generally high, accounting nearly half of the total restoration costs. The real costs are potentially higher than the estimation, especially if we include opportunity costs of displaced economic activities. The opportunity costs may not have to be internalized in all restoration projects, but they reflect the magnitude of anthropogenic pressures that restoration projects face. Benefits of peatland restoration over the long term may justify the costs. However, if peatland restoration projects have to internalize all of these costs, restoration efforts are unlikely to be sustained beyond project duration. There should be larger political scale commitments to address operating contexts of restoration projects, such as promoting good governance, land tenure security, ecosystem services market, incentives, political commitments, and funding support. The results of this study can inform policy-makers and practitioners for promoting peatland restoration projects in Indonesia with adequate policies, resource and funding.