<p>Ten samples of common red macroalgae (Rhodophyta) were collected from San Andrés and Providencia Islands (Colombia) to evaluate the potential as sources of photoprotective compounds. Aqueous extracts were analyzed for sun protection factor, UVA protection factor, and critical wavelength (λc). Mycosporine-like amino acids, known for their strong UV-absorbing properties, were identified and quantified using ultra-high-performance liquid chromatography coupled with diode array detection and tandem mass spectrometry (UHPLC-DAD-MS/MS), and quantified with diode array detection (UHPLC-DAD), respectively. Six mycosporine-like amino acids were detected: shinorine, palythine, asterine-330, porphyra-334, palythine-threonine, and palythinol. Among the tested species, <i>Laurencia obtusa</i> showed the highest total mycosporine-like amino acid content (1.54&#xa0;mg&#xa0;g⁻¹ DW) and the strongest UVB protection (SPF 23.14 at 20&#xa0;mg&#xa0;ml⁻¹ DW). <i>Acanthophora spicifera</i> collected in October 2023 exhibited the highest porphyra-334 levels and provided broad-spectrum protection, meeting the European Commission criteria for UVA coverage. Heatmap analyses revealed a positive correlation between mycosporine-like amino acid concentration and photoprotective performance. These results demonstrate the potential of Caribbean red marine&#xa0;macroalgae as sustainable sources of mycosporine-like amino acids for use in natural sunscreen formulations.</p> Graphical Abstract <p></p>