This paper presents the results of a baseline study of settlements built on water (kampung air) along the coast and rivers of Borneo. Using remote sensing data we measured the extent of water villages and estimated their number of households and inhabitants. We estimate that water villages cover an area of approximately 25 sq. km, housing 215,000 inhabitants. Though water villages are closely routed in Malay customs and traditions, it appears that other communities have also moved in, making use of relatively cheap accommodation. Further research is advocated, especially in view of the fact that climate change and sea level rise will reduce land areas suitable for housing construction.