The commensurate-incommensurate transition of a system of 20,736 krypton atoms on a graphite surface is studied by molecular dynamics computer simulations. The weakly incommensurate phase consisting of commensurate regions separated by a network of incommensurate domain walls is investigated at various temperatures and coverages. At low temperatures a honeycomb structure is observed. For increasing temperatures, the domain walls are found to fluctuate more and more out of the symmetry directions. They broaden considerably and show increasing surface roughness. © 1984.