Bangkok is one of the largest big cities in the world. This article shows how, during the decades 1970 to 2000, the public policies for opening up the economy and furthering the industrialisation of Thailand combined with the existence of specific comparative advantages to make the Southeastern coastline of the Central Region the cornerstone of the country’s development. The corresponding spatial growth, as a result of a structuring effect of urban development corridor processes at work, offers an ideal viewpoint to observe the forms contemporary megapolisation takes at the interface of the combined dynamics of globalisation, industrialisation and metropolisation.