ABSTRACT:
Introduction. Ensuring equitable access to primary health care in the Amazon remains a major public health challenge due to vast territories, dispersed populations, seasonal river dynamics and increasing climate related extremes. This study aims to evaluate access to services, continuity of care and equity outcomes associated with Fluvial Primary Health Care Units in riverine and traditional communities within climate sensitive territories of the Brazilian Amazon. Methods. A mixed methods situational diagnostic study was conducted between March and May 2025 in 51 municipalities across five states of the Brazilian Amazon. Data were collected through 227 semi structured interviews with managers, health professionals, community health workers, river transport workers and service users, combined with direct observation of UBSF operations. Results. Fluvial Primary Health Care Units expanded access to primary health care for remote communities by reducing travel time, costs and service discontinuity. Among all constructed units, 71.8 percent were credentialed and federally co funded. However, only 49 percent performed regular expeditions in 2024, and navigation was interrupted during drought months in more than 60 percent of the territories. Socioeconomic vulnerability increased dependence on UBSF for consultations, medications and preventive actions. Despite limitations, users reported high satisfaction, trust and strengthened longitudinal relationships with health teams. Community health workers facilitated user mobilization, continuity of care, health promotion and culturally appropriate communication. Conclusions. Fluvial Primary Health Care Units are a strategic response to health inequities in the Amazon under climate change. Strengthening this model requires sustained financing, climate‑adaptive logistics for flooded regions, regular expedition planning and integration with territorial health governance. Expanding the number of Fluvial Primary Health Care Units contributes to universal health coverage, equity, and the Sustainable Development Goals in vulnerable regions.