Emerging adults are a hard-to-recruit population for health researchers, as many do not routinely access health care services and are best recruited outside clinical settings. Social media and research volunteer registries (e.g., ResearchMatch) offer great potential among this population, yet a comparison of these two recruitment methods has not been done. To compare participant enrollment and completion rates, participant demographics, and recruitment costs between recruitment methods (social media advertisements compared to ResearchMatch) deployed with a sample of female-bodied emerging adults. Female-bodied emerging adults were recruited from October to November 2022 via ResearchMatch and social media (Instagram and Snapchat) advertisements. This analysis involves a subset of recruitment data from a larger institutional review board-approved study. Enrollment and survey completion rates were calculated using the number of individuals contacted and survey completion data from Qualtrics. Chi-square and independent t-test analyses were used to compare demographic data. Advertisement data collected included total cost, cost per click, link clicks, and paid impressions. Two hundred and forty-five emerging adults completed the survey, and 24 completed follow-up interviews. ResearchMatch and social media enrollment rates differed (58% and 39%, respectively). Survey completion rates for both methods were the same (~93%). Participants' ages and levels of education were significantly different. Social media resulted in recruitment of younger participants (18-21 years), and ResearchMatch garnered participants with a higher level of education. Differences in race were also significant, as social media recruited higher numbers of White participants. Lastly, the researcher-incurred cost per survey was $0 for ResearchMatch versus $13 for social media. While social media and ResearchMatch are both successful tools for research recruitment, each provides distinct benefits for recruiting specific populations. ResearchMatch offers a lower-cost option and access to an older emerging adult population with higher education, while social media provides access to a younger emerging adult population. This knowledge can be imperative for deciding which recruitment methods best fit research study needs. Future research should explore differences in race by recruitment method to highlight potential sampling biases or recruitment opportunities.