A method for passive alignment of adapters, enabling high-precision connection between components on a rigid or flexible substrate as part of a printed circuit board (PCB) is provided. Removable alignment structures are positioned in an alignment area on a PCB, where the alignment structures are in accordance with a patterned layer. An adapter, having adapter mating pins or holes, respectively, and adapter alignment pins, is placed on the PCB in the alignment area such that the adapter is aligned with the alignment structures. The adapter alignment pins are inserted into holes in the alignment structures. A ferrule is fixed on the PCB in the alignment area, and the ferrule holes or pins, respectively, are aligned to mate with the adapter mating pins or holes, respectively. The adapter is removed from the alignment structures, and finally the alignment structures are removed.