San Antonio, officially the Municipality of San Antonio, is a municipality in the province of Northern Samar, Philippines. According to the 2020 census, it has a population of 8,882 people. Its territory is coterminous with Dalupiri Island, just off the western coast of Samar Island at the south end of the San Bernardino Strait. The island's white beaches are considered an "undisturbed paradise" and future "premier tourist destination" in the Eastern Visayas region. San Antonio is also unique, as it is the only municipality in Northern Samar that also speaks Cebuano due to the influx of Boholano and Cebuano settlers in the past. The locals speak Waray which is the predominant language of Northern Samar and it is the main lingua franca in the island.