Although still accounting for a small segment of the global carbon market, the voluntary carbon market is a place for innovation where original solutions are proposed to deal with some challenges faced by the regulatory market, including efforts to value the occasional ancillary benefits of climate action, to simplify methodologies, or to guarantee the permanence of forestry assets. These innovations are reflected in the different standards used for voluntary offset projects and may provide some valuable lessons for on-going post-2012 negotiations. This study analyses two aspects of these standards: the type of projects they attract, and the transaction costs entailed by their procedures. Projects certified by “basic carbon standards” such as the VCS, the VER+ and the CCX are very similar to regular CDM projects, albeit for their size which can be smaller. Projects certified by “multiple benefits carbon standards” such as the GS and the CCB Standards however tend to be more diverse than CDM projects, both in terms of project location and technology. For large-scale projects, transaction costs can differ by up to 100% between standards, although they remain small compared to credit prices. For small-scale projects however, they can represent a real burden with costs around 2-3 €/tCO2e. The analysis of the internal rate of return (IRR) of hydro projects leads to a similar conclusion: as overall project costs dwarf certification costs, the choice of the standard has little influence on the IRR. However, for projects that require lower initial investments, such as biogas capture or manure management, the conclusion could be very different.