Background and Aims <p>Soil microdialysis is an emerging <i>in-situ</i> sampling technique that mimics bidirectional exchanges of chemicals in the rhizosphere; however, its effectiveness in predicting plant uptake of trace elements remains underexplored. This study aimed to evaluate microdialysis as a bioavailability assessment tool relative to established methods.</p> Methods <p>Using radish (<i>Raphanus sativus</i> L.) as a model plant, we assessed the potential of microdialysis to estimate bioavailable metal(loid) concentrations predictive of plant uptake. Microdialysis was compared with diffusive gradients in thin films (DGT), Rhizon samplers, and bulk extractions across 16 amended soils varying in pH, organic matter, and texture. Different perfusates, including low-molecular-weight organic acids, were tested to simulate rhizosphere processes.</p> Results <p>Microdialysis-derived concentrations of arsenic (1.3–42.4&#xa0;μg L⁻¹), cadmium (0.1–32.6&#xa0;μg L⁻¹), manganese (1.1–39081.7&#xa0;μg L⁻¹), lead (0.3–108.8&#xa0;μg L⁻¹), and zinc (1.9–910.0&#xa0;μg L⁻¹) varied over 1–5 orders of magnitude and showed significant correlations with radish tissue accumulations (r = 0.56–0.87, <i>p</i> &lt; 0.01), performing comparably or superior to other methods. Organic acid perfusates enhanced metal solubilization, particularly in calcareous soils, though they did not directly indicate plant bioaccumulation.</p> Conclusions <p>Soil microdialysis has been proven effective for estimating the availability of selected trace elements and investigating soil–plant interactions, supporting applications in precision agriculture and environmental risk assessment.</p> Graphical Abstract <p></p>