The effects of steam addition during calcination on the carbonation behavior of calcium-based sorbents in cyclic calcination/carbonation experiments were investigated. Variations in the CaO conversion rate during carbonation were measured to evaluate the influence of operating conditions and particle size on the carbonation reaction in kinetic- and diffusion-controlled reaction regimes. Surface sintering and particle aggregation during cyclic calcination/carbonation affected the sorbent surface area, pore volume, and possibly the pore size, resulting in less sorbent recyclability and a trigger time retard in the fast kinetic-controlled carbonation. Steam addition during calcination positively affected the recyclability of the sorbents and altered the carbonation behavior.