This dataset includes 3D sagittal left otolith meshes obtained from 339 individual red mullet (Mullus barbatus) specimens. These samples were collected from 17 distinct geographical locations spanning the whole Mediterranean Sea. Recorded biological parameters include fish total length (TL, ranging from 125 to 238 mm), total weight (W, ranging from 14.9 to 168.0 g), sex, and sexual maturity staging. The 3D otolith dataset consists of high-resolution meshes obtained through microtomography (29.2 m voxel size). The dataset provides valuable insights into the morphological variability and population structure of red mullet populations in the Mediterranean Sea.