The Hispanic, Latino, or Spanish (hereafter, “Hispanic”) populations in the U.S. bear a disproportionate burden of COVID-19-related outcomes, including disease incidence and mortality. Developing culturally appropriate national public health services for Hispanic persons remains a challenge. This study examined the association of heritage and language preference with COVID-19 testing (tested vs. not tested) and vaccination (vaccinated vs. not vaccinated) outcomes among Hispanic participants from 18 Rapid Acceleration of Diagnostics-Underserved Populations (RADx-UP) projects (n = 3308; mean age = 44.1 years [SD = 14.9], 60% women; 83% spoke other than English at home). Generalized estimating equation models adjusted for age, gender, education level, income, insurance coverage, geographic region, comorbidities, and prior infection. Relative to Mexican heritage, individuals identifying as Puerto Rican or Dominican were more likely to test for COVID-19, and South American heritage was associated with higher testing and vaccination rates. Speaking Spanish or another language at home was associated with increased testing compared with speaking English at home for individuals who preferred not to report their heritage, and increased vaccination for those with Mexican, Cuban, or Central American heritage. This study highlights heterogeneity in testing and vaccination behaviors among Hispanic populations based on heritage and language preference, underscoring the diversity within the U.S. Hispanic community. In contrast to other studies on linguistic acculturation and health care utilization, our study found that a language other than English spoken at home was associated with greater vaccine uptake. That is, enculturation – the retention of Spanish language and presumably of Hispanic cultural norms – was linked with being vaccinated.