The development of estuarine epibenthic fouling was monitored over a 19‐wk period on oyster shells sequentially deposited onto river bottom experimental plots during the summer of 1985. Each of the shell groups became fouled more rapidly than the ones deposited before it with the equilibrium fouling coverage for all four groups occurring by the time of the highest recorded water temperature in mid‐August. Sediment and detritus contributed 42–59% of shell coverage (both shell sides combined) while attached sessile organisms contributed an additional 14–37% of the total covered area. A detrended correspondence analysis ordination was used to depict changes in epibenthic biofouling community structure through time. With time, the species composition of all four shell groups both changed and became more similar to one another. The initial dominant biofouling species on each of the four shell groups reflected the settling patterns of larvae in the water column at the time of deposition of each shell group, but with time other species began to replace the initial space dominants. Disturbance of the experimental shells was evident and it is believed that such disturbances free substrate space at a rate sufficient to allow a changing array of epibenthic biofouling organisms in the water column to become established on the freed spaces and eventually replace prior dominants. Thus, the biofouling of shells on a natural estuarine river bottom continually changes in its community structure over time.