Electronic assemblies including coreless substrates and their manufacture using electrolytic plating, are described. One method includes providing a core comprising a metal, and forming a dielectric material on the core. The method also includes forming vias in the dielectric material, the vias positioned to expose metal regions. The method also performing an electrolytic plating of metal into the vias and on the metal regions, wherein the core is electrically coupled to a power supply during the electrolytic plating of metal into the vias and delivers current to the metal regions. The method also includes removing the metal core after the electrolytic plating of metal into the vias. Other embodiments are described and claimed.