Informal learning spaces play a significant role in enriching student experiences in learning environments. Such spaces are becoming more common, resulting in a change to the spatial configuration of built environments in higher education. However, previous research lacks methods to evaluate the influence of the spatial design characteristics of informal learning spaces on student preferences and their activities within. This paper aims to tease out the spatial design characteristics of informal learning spaces to examine how they shape students’ preferences in terms of their use of the spaces and what they do within them. The two case studies selected for this study, both in the UK, are the Diamond at the University of Sheffield, and the Newton at Nottingham Trent University. A mixed-methods study is applied, including questionnaires, observation, interviews, and focus groups. Six significant design characteristics (comfort, flexibility, functionality, spatial hierarchy, openness, and other support facilities) that influence student use of informal learning environments are identified. These can be used to inform future design strategies for other informal learning spaces in higher education.