The M5 Crop seismic regional profile in the Ionian sea is a complete cross-section of the Apennines and related foreland. From off-shore eastern Calabria to the southern prolongation of the Puglia-Salento into the Ionian sea, the profile shows eastward dipping normal faults, the frontal active accretionary wedge, the underfilled foredeep in the Taranto trench, and the foreland in the Apulian swell. Peculiar features are: the narrow accretionary wedge which is topographically and structurally deeper than the foreland; frequent triangle zones in the accretionary wedge; earlier foredeep deposits incorporated and deformed in the accretionary wedge, and at places buried by thrust-top basin deposits; the high 8 degrees -10 degrees dip of the regional monocline; the foreland which is folded by a 100 km wide crystallithospheric anticline that determines to the northwest the emergence of the Puglia region; in the eastern side of the Apulian doming, at depth the Apulian carbonate platform seals an half-graben of Late Permian(?)-Early Mesozoic age. These observations might be useful for interpreting structures inland, to the north along mainland Apennines and the foreland.