Oil sands coke is a byproduct of oil sands upgrading, which potentially can be used for the production of low cost activated carbons. Activation of oil sands delayed coke was performed by partial CO2-gasification in a tubular fixed bed reactor at 900°C. Pore development during activation initially proceeded almost exclusively by micro-pore formation, and the reaction appeared to follow a shrinking core model. Surface areas up to 646 m2/g were obtained, and coarser particles reached lower maximum surface areas at lower levels of burn-off than finer particles. Pre-oxidation in air at 270°C resulted in higher maximum surface areas.