Upon his return from Hong Kong, Santos played rugby with the Bahay Bata Orphanage. The team defeated the British School Manila once which Santos considers as a milestone moment with Bahay Bata.[5] The Santos family and friends later established the Makati Mavericks Rugby Club.[1]
Santos played rugby for ISM during his high school years. Outside of ISM, he also played for the New Zealand-based North Harbour Rugby Union in the Manila 10s. He was also part of his family's Makati Mavericks playing in domestic 7s, 10s, and 15s competitions.[3]
Santos was part of Harvard rugby during his college years. In his freshman year in 2018, he was elected as vice-captain before becoming the second player of Filipino descent to captain the Harvard team after Jaime Alfonso Zobel de Ayala. He helped the team finish second at the 2022 Collegiate Men's Rugby D1-AA National Sevens Championships–the best finish of the team in the tournament. He was also named in the 2023 Division I All-American.[6]
Santos has been part of the Philippine national rugby team youth program specifically at the Under-14 (U14), U16, U18, and U19 levels.[3]
Santos later switched to the United States, suiting up for the United States U23 team in 2021.[7] He later become part of the United States senior national rugby sevens team around early 2023.[5][6]