Rapid demographic changes and heavy reliance on informal care pose significant challenges to meeting long-term care (LTC) needs in China. Understanding changes in unmet LTC needs across different times and places can inform future LTC system planning and care resource allocation, identifying emerging care needs and services gaps in different regions. Drawing on data from 6,030 urban and 5,070 rural residents in the Chinese Longitudinal Health Longevity Survey 2005–2017/18, this study investigates variations in unmet LTC needs across different age groups, periods and birth cohorts among Chinese older adults and their place-based rural–urban differences. We applied the age-period-cohort interaction model to disentangle the three temporal processes, and found that, overall, rural older adults experienced higher risk of unmet LTC needs and had larger variation in age effects, yet the age, period and cohort effects on unmet needs among rural older people differed from their urban counterparts. Although ‘younger’ older adults (aged below 85) had fewer care needs than older adults, they had a higher risk of experiencing unmet needs. The risk of having unmet needs did not change significantly over the 12 years, though unmet LTC needs were more pronounced among more-recent cohorts than previous generations, especially in urban areas. The findings contribute to the social gerontology debate regarding changing patterns in unmet LTC needs, and provide crucial policy insights, underscoring the necessity of targeted interventions to address ‘younger’ older adults’ care needs and increased investmed in the formal LTC system to tackle the escalating care gap.