Centrifuge physical modelling of light nonaquaeous phase liquid (LNAPL) transport in an unsaturated sand is discussed with regard to the similitude of the resulting three-fluid flow. Three model series are reported: the first to establish a reproducible unsaturated moisture–suction profile; the second to examine the modelling of models methodology for evaluating similitude of an LNAPL release into an unsaturated fine sand; and the third to prototype-scale data sets for 1000 L surface LNAPL releases at two different rates. Results show that a slower release rate produces deeper LNAPL penetration, and the reasons for this behaviour are discussed. An inexpensive and readily available numerical code called SWANFLOW was used to independently simulate the prototype release rates, and the results are compared with the centrifuge data. The numerical simulations produced compatible predictions of short-term oil transport but did not predict the observed longer term fate of the LNAPL in this highly nonlinear imbibition–drainage problem. A numerical code that incorporates hysteresis between the imbibition and drainage curves would be expected to produce more complete long-term predictions. Key words: centrifuge modelling, numerical simulation, LNAPL fate, unsaturated sand.