Latinx represent the second largest ethnic group in the USA and remain significantly underrepresented in research studies. Efforts to better include Latinx make use of community-engaged research (CEnR) approaches, peer-navigators, and cultural humility training for research teams. While these efforts have led to slight increases in Latinx participation, studies to identify strategic practices for better inclusion of Latinx participants are needed. The objective of this study was to qualitatively examine factors leading to successful recruitment and retention of Latinx participants in the Promoting Activity and Stress Reduction in the Outdoors (PASITO) intervention. For this intervention, 99 low-income Latinx clients in a local community were contacted and 52 participants were recruited (53%). All were retained in the 3-month intervention. Of these, 12 were interviewed within 6 months of the close of PASITO by bi-cultural and bi-lingual non-research staff. They conducted one-on-one structured telephone interviews. Of the twelve participants, three (25%) were men, nine (75%) were women, and the mean age was 43.7 (SD = 8.7). Four critical themes for the recruitment and retention of Latinx populations emerged from the interviews: (1) importance of insider researchers; (2) sense of community and belonging; (3) responsive programming; and (4) health-promoting activities. These findings support the significant role insider researchers can play, and social identity theory provides a useful framework for understanding the role of insider researchers in recruiting and retaining Latinx, and likely other minoritized groups, in clinical studies. Insider researchers possess the skills, training, community cultural wealth, in-depth understanding of their communities, and structural competencies that position them to carry out more inclusive studies to address the needs of marginalized communities and advance science.