The aim of this study was to estimate the values to protect the health of the Great Barrier Reef (GBR) at the national level and to examine the effects of distance decay on valuation estimates. A split-sample choice-modelling experiment was conducted in six locations: a regional town within the GBR catchment area (Townsville); Brisbane, the state capital approximately 450 km from the southern limit of the GBR; and four other capital cities (Sydney, Melbourne, Adelaide and Perth) ranging from nearly 1,000 km to over 4,000 km from Brisbane. The results suggest that the average WTP across Australian households is $21.68 per household per annum for five years. There was some evidence of distance decay in values. Most decline occurred once outside the home state, and little further decline once away from the east coast. There was no evidence to suggest any difference in patterns of use and non-use values. The values of the potential future users were most influential in determining WTP estimates.