This study investigates the impact of cross-cultural adjustment and subjective well-being on the achievements and intentions of Spanish self-initiated expatriates (SIEs) regarding their decision to stay abroad or return to Spain. Using resource conservation theory, the research examines how SIEs’ agency influences their adjustment and well-being, thus affecting their achievement and propensity to repatriate. A tailored online survey was administered to Spanish SIEs, incorporating validated scales to cross-cultural adjustment, subjective well-being, and intention to stay abroad. Using non-probability sampling, a final sample of 309 SIEs was obtained. Data analysis employed partial least squares structural equation modelling (PLS-SEM) to validate the hypotheses. The results show that improved adjustment and well-being of SIEs correlate with improved achievement and reduced likelihood of repatriation. These results underline the importance of cultural adjustment and subjective well-being in shaping SIEs’ expatriation experiences and their intentions to stay abroad. Furthermore, the research lays the groundwork for future comparative studies and underlines the need for home institutions to facilitate the repatriation process. Moreover, the implications of the findings for management offer ideas for improving the experiences of SIEs abroad and recognising their value as assets to both national and global organizations, while addressing the challenges associated with repatriation.