The high organic carbon (C org ) sequestration ability of biochar can greatly contribute to atmospheric CO 2 removal for global C neutrality. These climate-positive services of biochar are traded as C credits on international C trading platforms through reliable methodologies. Here, we reviewed the international biochar C credit certification methodologies and quality standards to build foundations for biochar C credit trading in Korea. The quality of biochar includes the quantity of C org sequestered over 100 years, the content of toxic contaminants below their threshold values, and the biochar properties related to soil fertility, as described by European Biochar Certificate (EBC) and International Biochar Initiative (IBI) certification guidelines. The higher amount of C org sequestered over 100-year in biochar is ascribed to the lower the molar H/C org and O/ C org ratios, resulting from pyrolysis of feedstock at a high temperature over 350°C. For assuring the permanence of biochar, the threshold value of molar H/C org ratio is 0.7 in both EBC and IBI. Besides, EBC standards also have the threshold value 0.4 of a molar O/C org ratio for all biomass and require a pyrolysis condition of exceeding 500°C for 3 min at minimum for animal-derived biomass. Quality-certified biochar can be used for C credits. Biochar C credit is the amount of net CO 2 -eq removed over 100-year by the biochar activity, i.e., biochar C org sequestered over 100-year minus greenhouse gas (GHG) emissions over the biochar life cycle. The three voluntary C credit trade platforms with their own biochar methodologies are Puro.earth with life cycle assessment, Carbonfuture with C-sink certification, and Verra with UNFCCC Clean development mechanism (CDM) methodology. All three methodologies present standards for permissible biomass for feedstock, energy efficiency and by-product treatment for production, permissible matrices and tracking system for end use, and the third-party verrification. On a regional basis in Korea, where biochar feedstock is mainly biogenic waste, GHG emissions during biochar lifetime mainly depend on the production stage. In pyrolysis facilities that meet EBC and Verra's high-tech standards, GHG emissions during the production stage could be assumed to be very low. However, low-tech facilities with high GHG emissions during biochar production could deteriorate biochar C credits. Therefore, securing biochar C credits could be achieved through the modernization of pyrolysis facilities. Besides, it is essential to establish a process-oriented measurement, reporting, and verification systems, to ensure scientific reliability of biochar C credit certification.