This technical guidance document is a practical guide for developing and implementing electronic catch documentation and traceability (eCDT) technologies and systems, principally for marine capture fisheries, that can be aligned to the different capacities, circumstances, and needs of ASEAN member states (AMS) and the Coral Triangle Region countries. Supported by the Oceans and Fisheries Partnership (USAID Oceans), this guidance aims to facilitate the national-level transition from paper-based to digitized catch documentation systems and promote transparent and financially-sustainable eCDT technologies and systems.