This study examines the reliability of cross-national subjective well-being (SWB) survey data, by corroborating the persistently high SWB-rankings of Denmark through a comparison to Sweden and Australia, two countries with similar or superior social, economic, and health indicators. Our research focuses on both the affective and the cognitive component of SWB, with a special emphasis on the affective component. We investigate four potential measurement issues that could contribute to Denmark’s elevated SWB scores: linguistic inconsistencies in survey translations, variations in answering scale usage, recall bias of affect, and positivity bias in life satisfaction judgments. To address these concerns, we utilize multi-group confirmatory factor analysis, analyse emotion-focused anchoring vignettes, examine affect items across varying time frames, and contrast overall life satisfaction assessments with those of domain-specific satisfaction. Despite accounting for various potential measurement issues, our results reveal that Danes consistently report higher SWB than their Swedish and Australian counterparts, although the differences are small for several of the measures. This finding implies that the SWB survey-data is reliable in this case, and that Denmark's high SWB rankings are not attributable to measurement biases but may indeed signify genuinely high levels of SWB. This paper adds to the growing body of literature on cross-national SWB comparisons and might provide insights for researchers aiming to compare well-being across countries.