Abstract The hopping of a tracer in a two-dimensional lattice gas model with low coordination number is examined. The model consists of noninteracting particles except that double sites occupancy is forbidden. An arbitrary concentration, c, on a honey-comb lattice is assumed. The correlation factor, f(c), is estimated by the Monte Carlo simulation, and compared with theoretical expressions. The correlations over two successive jumps of a tracer are in general insufficient to account for f(c) data. Inclusion of correlations over three and four jumps improves the description. The theory of Nakazato and Kitahara 1 gives a satisfactory description of the data.