Data are reported on shell length (mm), dry shell weight (g), dry flesh weight (g), and condition index in mussels farmed in the Mar Piccolo of Taranto from 2004 to 2020. From 2004 to 2012 data were collected in summer in one station in the First Inlet of the basin. In 2013, data were collected in spring in the First Inlet and in summer in the Second Inlet. In 2014, data were collected in spring in the First Inlet and in summer in the Second Inlet and in the near Mar Grande. In 2015, data were collected in winter and spring in the First Inlet and in summer in the Second Inlet. Starting from 2016, data were routinely collected in spring in the First Inlet and in summer in the Second Inlet. Each season, 75 randomly selected mussels were measured, sampled from three breeding “camera” (five for each camera), at three different distances from the coastline (i.e. land, middle, off shore) (five for each distance).