The rare earth element (REE) signal recorded in a coastal system depends on which organism is used to read it, yet how differently co-occurring species capture that signal is rarely examined directly. REEs are increasingly recognised as emerging contaminants of global concern, yet their behaviour remains comparatively understudied in marine environments. Shallow-water hydrothermal vents enrich coastal waters and sediments with REEs, providing a natural laboratory for examining the transfer from the sediment to biota. At the shallow CO₂-vent system of Levante Bay (Vulcano Island, Southern Tyrrhenian Sea, Italy), we examined REE transfer across multiple matrices: sediment and three co-occurring, functionally distinct benthic organisms that intercept REEs through complementary exposure pathways, sampled at a low-pH (7.5) and a high-pH (8.16) site: the seagrass Cymodocea nodosa, the sea anemone Anemonia viridis and the goby Gobius incognitus. Bio-Sediment Accumulation Factor values (BSAF) remained below unity in every matrix at both sites, indicating limited transfer despite marked hydrothermal enrichment. Post-Archean Australian Shale (PAAS) normalised patterns, diagnostic anomalies, and multivariate ordination indicated that a single sediment source was not merely reflected in the organisms. Instead, it was reworked into three distinct biotic signatures. These signatures ranged from a passive, light REE-enriched profile to a biologically fractionated, heavy REE-enriched one, with the goby exhibiting a low, weakly structured profile. Across these analyses, matrix identity structured REE accumulation more consistently than the pH gradient. Reading the REE signal across multiple matrices, therefore, resolves features of its distribution that no single bioindicator captures, providing diagnostic information directly relevant to monitoring the quality and conservation status of coastal ecosystems.