This study analyzes the impact of general trust on subjective well-being (SWB) in Korea, Japan, and China using data from the World Value Survey. To address potential issues such as reverse causality (or endogeneity/simultaneity), where SWB may be causing the trust outcome, and omitted variables, where the observed association reflects a correlation between trust, SWB, and some unmeasured characteristic, the paper employs an instrumental variable design. This design allows for the interpretation of the findings as causal. Consequently, the study concludes that trust, instrumented by the highest education level and disbelief, has a significantly positive effect in these three countries, resulting in a much higher level of SWB than the ordinary OLS results. Specifically, this effect is even stronger in Korea and Japan than in China.