BackgroundIt is unclear how strong and long lasting the effects of recurring COVID-19 pandemic restrictions are on older adults’ loneliness. Methods457 retired older Austrians (60+) provided 9,489 repeated observations of loneliness across 30 survey waves of the Austrian Corona Panel Project between March 2020 and March 2022. Ordinal mixed regression models were used to estimate the effect of time-varying country-level strictness of COVID-19 restrictions (stringency index, range=0–100) on older adult's loneliness. ResultsThe proportion of older adults who reported to be often lonely correlated (r = 0.45) with the stringency index over time: both peaked during lock-downs (stringency index = 82, often lonely = 10%-13%) and were lowest during the summer of 2020 (stringency index = 36, often lonely = 4%-6%). Results from regression models adjusted for the number of new COVID-19 cases and deaths indicate, that when the stringency index increased by one point, the odds for loneliness increased by 2%. Older adults who lived alone were more likely lonely during the pandemic and were more affected by COVID-19 restriction measures compared to those living with others. ConclusionsMore stringent COVID-19 restrictions were associated with an increase in (situational) loneliness among older adults in Austria, and this effect was stronger among those who lived alone. Efforts should be made to enable older adults, in particular those who live alone, to allow for save in-person contact in case of (future) periods of strict pandemic restriction measures.