DNA barcodes and morphological observation were used to evaluate the number of species within the genus Corallina sensu lato in Atlantic Iberia and to identify a set of morphological characters that may discriminate them. Five species were detected: (i) C. officinalis, (ii) C. caespitosa, (iii) Ellisolandia elongata, (iv) Corallina sp. 1, and (v) Corallina sp. 2. The first three species were widespread whereas Corallina sp. 1 was only detected in southern Atlantic coasts of Iberia and Corallina sp. 2 occurred both in the Atlantic and the Mediterranean, nevertheless, with morphological and molecular differences. The widespread occurrence of the recently described C. caespitosa along Atlantic Iberia is substantiated with sequence data for the first time; it spans from the Bay of Biscay to Andalusia and the French Mediterranean. Molecular support is also provided for the presence of C. officinalis and E. elongata in Atlantic Iberia. Plants of C. officinalis were correctly identified attending to their external morphology, however two distinct species were detected under the two forms of C. elongata (“typical” and “elongated”) reported for Galicia in the literature (C. caespitosa and Ellisolandia elongata, respectively). Plant size, habit, branching, and shape of intergenicula seem the most informative morphological characters to discriminate among the various members of Corallina s.l. in Atlantic Iberia.