There are millions of tonnes of petroleum coke stockpiled worldwide, but to take advantage of this potential resource, a better understanding of how to activate this feedstock with less waste is required. The impact of steam addition during chemical activation of petroleum coke with a high sulfur content (similar to 6.5 wt%) was evaluated with two chemical agents (KOH and NaOH), chemical molar ratios (from 0.12 to 1.02 or mass ratios from 0.5 to 3) and activation times (0 to 120 min) at 1073 K. Based on the yield and total pore volume developed, coactivation of KOH and steam was an effective way to reduce the amount of chemical agent required, while widening the pores from similar to 1 nm to up to 4 nm. In contrast, the addition of steam to the activation with NaOH resulted in less pore development and essentially no change in the pore size. At the activation conditions, there is likely a molten phase around the particles that slows steam gasification and has a composition that changes with the introduction of steam.