Tracking the decline of first marriage in South Korea: Timing, quantum decline, and pandemic disruptions

Background: In South Korea, where most births occur within marriage, the country’s record-low fertility has put renewed attention on the long-term decline in first marriage. Despite rising policy and academic interest, systematic demographic analyses that disentangle structural and timing components of nuptiality change remain limited, especially in East Asia. Objective: This study examines trends in the quantum and timing of first marriage in South Korea from 1993 to 2023 and assesses whether the decline reflects structural retreat, postponement, or both. Methods: Using legally registered marriage data from the national vital statistics system, we construct three period indicators: the total first marriage rate (TFMR), the period proportion ever married (PPEM), and a tempo-adjusted PPEM (PPEM*). We estimate the never-married population using age-specific proportions from the census, applied to mid-year resident registration data. All indicators are calculated separately for men and women. Results: Both TFMR and PPEM declined markedly over three decades. Among women, PPEM and PPEM* showed parallel trajectories, indicating a structural retreat from marriage. Among men, PPEM fluctuated more sharply, and its widening gap with PPEM* after 2015 reveals stronger tempo effects. The temporary convergence in 2020 reflects compositional change due to a sharp fall in international marriages during the pandemic. Conclusions: The findings reveal a sustained decline in first marriage for both sexes, with men showing lower levels and greater sensitivity to timing shifts and external disruptions. Contribution: By extending tempo-adjusted analysis to first marriage, this study offers new insights into nuptiality decline in East Asia’s ultra-low fertility context.