This paper estimates Thailand's long-run tourism demand elasticities for a set of origin countries by applying dynamic ordinary least squares. A detailed analysis of the potential competing destinations for each origin country is performed to ensure a precise coefficient for the substituting elasticity. A long-run static model of time varying parameter is then used to analyse the effects on the estimation of a potential structural change caused by the 1997 economic crisis and the subsequent change in exchange rate policy. The results show that there are different demand elasticities for each origin market and that own price elasticity is lower than substituting price elasticity for most origin countries. These findings indicate that price-setting strategies should be specific for each origin market and that information about prices in competing destinations needs to be considered. Moreover, the results show that there was a structural change in 1997 that severely affected the estimation.