As campuses wish to stimulate interactions among different campus users, we aim to identify why some locations are successful in fostering unplanned meetings while others are not. This can help campus managers, directors, and other practitioners to optimize their campus to facilitate unplanned meetings between academic staff and companies. Findings of a previous survey were discussed in five focus groups, which were transcribed and thematically coded. Three separate theme groups were identified: function (food, drinks, events, work, facilities), space (distance, experience, accessibility, characteristics), and organization (coherence, culture, organization). Time was an overarching constraint, influencing all other themes. There were three natural moments for unplanned meetings: during short breaks, lunch breaks, and events. The outcomes suggest a 5-minute campus as the environment of interaction; a campus where natural moments, locations, and travel time for unplanned meetings are designed and aligned: (1) under 5 min walking for short workplace breaks, (2) approximately 5 min travel time for lunch breaks, and (3) over 5 min travel time for events, depending on the event length and anticipated knowledge gain.