## **Background** In recent years, understanding the macroeconomic contributions and social value of sports has advanced globally. While traditional sports management literature heavily focuses on subjective well-being and social capital, few empirical studies have quantified the mechanisms translating these intangible psychological benefits into macro-level economic indicators, such as Gross Domestic Product (GDP). ## **Purpose** This study focused on rugby to quantify the socioeconomic value of sports-induced well-being. Specifically, it elucidated the causal pathways through which rugby match watching enhances labor productivity and simulated its ultimate contribution to national GDP and Social Return on Investment (SROI). ## **Methods** A web-based survey was conducted from June 11 to 23, 2026, targeting a sample of 14,835 rugby fans in Japan. The survey captured demographics, viewing behaviors, and self-reported improvements in psychological, interpersonal, and physical dimensions. Data analysis employed descriptive statistics, co-occurrence network structure analysis of open-ended happiness descriptions, and path analysis to test the direct and indirect effects of well-being factors on work productivity. **Results** Descriptive statistics revealed high engagement among respondents, with rugby watching yielding substantial perceived benefits for stress relief, social bonds, and social well-being. The co-occurrence network analysis visualized that the peak moments of happiness are deeply tied to a sequential “rugby story”—ranging from a team’s victory and dynamic plays to the unique post-match “no-side” spirit. Path analysis demonstrated a dual-structured transmission mechanism: individual physical health (beta= 0.335) and stress relief (beta = 0.325) exert powerful direct effects on work productivity. Simultaneously, corporate sponsorship favorability (beta = 0.328) functions as a major trigger that fosters overall social happiness, which indirectly boosts productivity (indirect effect = 0.049). ## **Discussion/Conclusion** The self-reported work productivity increase (28.36%) was converted into a conservative macroeconomic model (10% realization rate) to prevent overestimation bias. Assuming an affected labor population of 200,000 workers, regular rugby watching is estimated to create an annual economic value of 30.5 billion JPY (165 million EUR) through improved real productivity. Operationally utilizing the Japan Rugby Football Union’s 2025 budget (8.3 billion JPY) as the investment baseline, the estimated SROI ratio was 3.67. This study underscores that public and corporate investments in sports environments are highly efficient economic policies that mitigate workplace presenteeism, improve worker well-being, and tangibly support national macroeconomic growth.