The success of university campuses depends on the interrelations between creative encounters and the built environment, conceptualised here as spatial affordances for creativity. Such an interface plays a fundamental role in interactions for knowledge sharing and the exchange of ideas on campus. Due to campus public spaces generally being considered as the leftovers between buildings and classrooms, undermanaged, and overlooked, little is known about the extent to which this built environment enables or inhibits creative encounters in such spaces. The inner-city campuses and science parks (SPs) of Amsterdam and Utrecht, the case-studies of this research, differ in terms of their location relative to the city, their masterplan typologies and the arrangement of buildings. However, they are similar in terms of the aforementioned issues of public spaces. The novelty of this research is the attempt to overcome such issues using an innovative mixed-methods approach that tests the ‘spatial affordances for creativity’ with empirical data collection and analysis. This raises the importance of mapping, quantifying and analysing the spatial distribution of momentary perceptions, experiences, and feelings of people with methods such as volunteered geographic information (VGI). The results show that proximity between multiple urban functions and physical features, such as parks, cafés and urban seating are important when it comes to explaining the high frequency of creative encounters between people. Urban designers of campuses can use the applied method as a tool to plan and design attractive public spaces that provide creativity through the transfer of tacit knowledge, social well-being, positive momentary perceptions, sense of community, and a sense of place.