Compact city urban policies are promoting higher density housing outcomes across many metropolitan areas. Consequently, the development of higher density housing in the form of apartments is becoming a major feature of the contemporary urban housing market. Understanding the demand driving this market has therefore become a critical issue for planners. However, traditional housing market analyses offer limited insight into what is essentially a three-dimensional housing market operating in a spatially fragmented manner. This paper uses the concept of spatially discontinuous housing markets to unpack the structure of the current demand for apartments in Sydney and Melbourne, Australia’s largest cities. It therefore offers a new analytical tool to improve understanding of high density housing markets as well as providing new insights into how such markets are structured at a time when planning policies and markets are delivering significantly greater quantities of this form of housing in many comparable urban areas.