While informality has long been studied as a feature of governance in the global South, a growing range of accounts examine informal governing arrangements as endemic to cities and nations of the global North. This paper contributes to such scholarship by drawing attention to informal practices and mechanisms involved in the spatial management of sex work in the global North. Existing literature on the spatial management of sex work has long emphasised how informality shapes local sex work practices and mediates formal state-based regulation. We synthesise these studies to suggest three modes of informal governance: as component, catalyst and alternative to formal regulation. Through a case study of street-based sex work management in Christchurch, Aotearoa New Zealand, we discuss how informal governance emerged as a de facto component of formal regulation at the national scale and an alternative to formal regulation at the local scale. Specifically, we detail how an ambiguous regulatory environment, combined with highly localised understandings of spatial appropriateness, led to and influenced the informal management of sex work through a community-level partnership between local authorities, residents and sex worker advocates. In doing so, the paper advocates for more attention to the multi-modal and multi-scalar aspects of informal governance.