Observably, date palm continues to be affected under severe and prolonged episodes of agricultural drought. Nevertheless, the application of biostimulants may mitigate consequent effects. Since the role played by biostimulants in this regard remains illusive, this study proposes comparing the effects of selected arbuscular mycorrhizal fungi (AMFs) and compost (C) on droughted Boufeggous date palm plants. Two experiments were conducted under greenhouse (nine-month drought stress; 75% of field capacity (FC), 25% FC) and field (18-month drought stress; optimal irrigation, deficient irrigation (WD)) conditions. To evaluate whether field outputs corroborate greenhouse's, results were expressed as variation percentage (VP) and relative field biostimulant dependency (RFBD). AMFs + C significantly (p <= 0.05) favored mycorrhizal parameters (e.g., VP of mycorrhizal frequency enhanced by 97.87% under 25% FC and 137.83% under WD), shoot dry weight (VP increased by 82.41% under 25% FC and 88.89% under WD), and photosynthetic pigments (e.g., VP of chlorophyll b improved by 267.2% under 25% FC and 232.11% under WD). The application of C mostly improved osmolyte content and attenuated oxidative stress, and AMFs especially optimized soil physicochemical properties (e.g., VP of soil available phosphorus increased by 69.21% under WD), compared to controls. Furthermore, RFBD mostly rhymed with VP records. Interestingly, mycorrhizal traits, shoot dry weight, photosynthetic pigments, osmolyte content, and organic matter almost aligned across environments. In light of the outcomes of the present comparative study, potential biostimulant benefits are validated under a semi-arid scenario. Further investigation is, nonetheless, recommended.