Because of ablation injection, monatomic carbon is an important flow field constituent of ablative flow during planetary entry, particularly near the surface of the entry vehicle. Therefore knowledge of the transport properties for carbon species is required for calculating the flow field properties and surface heating. In this study, the transport collision integrals for each of the 18 molecular C2 states that dissociate into ground state carbon atoms are obtained. This is accomplished by fitting two-body semiempirical interaction potentials, for which the collision integrals are tabulated, to experimental and/or accurate theoretical calculations for each of these states. The collision integrals are used to calculate the diffusion coefficient, viscosity, and translational contribution to the thermal conductivity of monatomic carbon at 1-atm pressure form 1000¿K to 25,000¿K.