Sea-level rise poses major challenges to coastal land uses, and therefore to urban planning processes. In theory, if done well, urban planning can lead to responses to sea-level rise that are socially and environmentally sustainable. In practice, urban planning processes may fall short of this ideal. We use multiple methods to describe and analyse how urban planning processes have led to adaptation to sealevel rise in Lakes Entrance in Victoria, Australia. Adaptation has principally taken the form of restrictions on development on low-lying land. In this town, which is considered particularly vulnerable to sea-level rise, the urban planning process and its outcomes have been controversial and divisive. Policies at the state level were imposed rapidly on this particular local community, and were later applied across the state. Our findings support the emerging consensus that to be sustainable, urban planning needs to: facilitate local ownership of adaptation responses; build collective action within local communities and between local communities and different arms and levels of government; and be fair in its application across space and over time. Addressing these social dimensions of adaptation takes time, but they are a sine qua non of sustainable adaptation to sea-level rise.