On 7 January 2020, the southern region of Puerto Rico was struck by a 6.4 magnitude earthquake, followed by continual seismic activity. Our team performed secondary analyses to explore the relationship between exposure to seismic activity, protection (support) received, and barriers to health care access for cancer patients. Methods: The research team collected data from the database of a longitudinal case-control cohort parent study concerning the impact of Hurricane Maria in Puerto Rican cancer patients. The participants from the parent study were recruited in community clinics. The extracted data was collected from 51 cancer patients who completed the parent study’s interviews from January–July 2020 (seismic activity period). Barriers to health care were assessed using the Barrier to Care Questionaries (BCQ), which is composed of five subscales: skills, marginalization, knowledge and beliefs expectations, and pragmatics. Exposure to seismic activity and protection was assessed using their respective subscales from the Scale of Psychosocial Impact of Disasters. Results: The results showed a significant relationship between exposure to seismic activity and barriers to health care (p < 0.001) and its five subscales (p < 0.01). These results shed light on potential access to care barriers that could hinder cancer patient treatment in the event of a natural disaster.