Introduction Retained dwellings in depopulating coastal settlements may remain socially claimed and available for return or reuse after year-round occupation declines. This study conceptualises seasonal housing vacancy as a rhythmic land-use relation in which dwellings move among closure, repair, return, leasing, and seasonal operation, and examines its implications for coastal land governance.MethodsWe conducted an abductive qualitative case study of Miaozihu, Dongfushan, and Qingbang in the Dongji Islands, Zhejiang, China. Fieldwork covered the peak, transition, and low tourism seasons in 2023 and 2024. The dataset comprised 56 encounters, including semi-structured interviews and field conversations, supplemented by field observations and documentary materials. The materials were examined through thematic analysis and narrative interpretation to identify recurring relations across actors and sites and trace changes in housing trajectories over time.ResultsSeasonal vacancy developed as schooling, employment, and public services became concentrated in mainland towns, leaving dwellings physically closed but socially claimed and available for future use. Tourism reactivated retained housing selectively according to location, ferry access, repair feasibility, and regulatory conditions, producing uneven residential land value. Reopened guesthouses generated seasonal value while depending on water-supply schedules, waste transfer, ferry and cargo logistics, storm response, and protected-area governance. Administrative recognition was also uneven: ownership, leases, licences, and approved repairs gained greater standing than temporary labour, environmental care, and routine maintenance.DiscussionThe Dongji case shows that seasonal vacancy can reorganise residential land-use intensity and environmental-governance responsibility without visible land-cover change, turning private housing reuse into an island-wide governance issue. Rhythmic land use shifts attention from static occupancy status to the timing of retention, selective activation, and renewed closure. The findings support an approval process that records expected seasonal service demands and assigns responsibility before housing reuse begins.