In the development of Ciudad Fernandina de Vigan, the gateway of its trade and commerce had been confined to the unknown trading post in the tributary of the Mestizo River, known as the Port of Pandan. The Spanish colonization of the old town of Vigan started with the exploration by Juan de Salcedo of northern Luzon. He reached Vigan through the mouth of the Mestizo River, where the Port of Pandan was located. This was a trading post where you can find the inland boat called biray, a vessel with an average length of 18 meters and width of 5 meters. The biray had been used as commercial vessel in Northern Luzon with usual destinations that included Cagayan, Ilocos Norte, Ilocos Sur, and La Union. The existence in 1572 of the pre-Hispanic trading post was confirmed by San Agustin (De los Reyes, 1890), regarding early Spanish contact with the natives as they entered the gateway of Pandan Port, moving into the pre-Hispanic trading settlement of Vigan, including the very old neighboring pueblo called Bantay. Notably, the Ilocos shipping tradition in the trading of agricultural and native products of the region is mentioned in the description of the Philippine Islands dating back to 1618. The grandeur of the Port of Pandan as the gateway of local mercantile development that supported the trade and commerce of Ciudad Fernandina de Vigan reached economic prosperity from 1919 through 1935, during the American period. In the 1970s, the last biray docked on this port, in the neighboring barangay of Fuerte. Historians and archaeologists have undertaken underwater cultural heritage assessment around the relics of a biray that was excavated in the Municipality of Caoayan. The study provides historical and cultural perspectives of the biray from its pre-Hispanic identity to its post-war trading contributions to the economy of Ciudad Fernandina de Vigan.