We investigated the organelles involved in the biosynthesis of fatty acids (FA) derivatives in the cortical cells of Laurencia translucida (Rhodophyta) and the effect of these compounds as antifouling (AF) agents. A bluish autofluorescence (having emissions at 500 nm) within L. translucida cortical cells were observed above the thallus surface via laser scanning confocal microscopy (LSCM). A hexanic extract (HE) from L. translucida was split into two isolated fractions called hydrocarbons (HC) and Lipids (LI), which were injected in high performance liquid chromatograph (HPLC) coupled to a fluorescence detector and revealed the same autofluorescence pattern observed by LSCM analyses (emissions at 500 nm) in the LI fraction. These fractions were analyzed by gas chromatography mass spectrometry (GC-MS), which revealed that docosane is the primary constituent of HC, and hexadecanoic acid and cholesterol trimethylsilyl ether are the primary components of LI. Nile red (NR) labelling (lipid fluorochrome) presented a similar cellular localization to that of the auto-fluorescent molecules. Transmission and scanning electron microscopy (TEM and SEM) revealed vesicle transport processes involving small electron-lucent vesicles, from vacuoles to the inner cell wall. Both fractions (HC and LI) inhibited micro-fouling (HC: lower minimum inhibitory concentration - MIC values of 0.1 μg.mL-1; LI: lower MIC value of 10 μg.mL-1). The results suggested that L. translucida cortical cells can produce FA derivatives (e.g., HCs and FAs) and secrete them to the thallus surface, providing a unique and novel protective mechanism against microfouling colonization in red algae.