ObjectivesLittle is known about the sexual networks of young transwomen, leaving a major gap in what we know about transmission dynamics and the elevated rates of HIV in this population. The objective of this study was to understand partnership-level factors associated with condomless anal sex among young transwomen.MethodsA secondary data analysis of the sexual partnerships of young transwomen was conducted using baseline data from the SHINE study. Generalised estimating equation logistic regressions were used to assess for partnership-level associations between partnership type, age, injection drug use and racial concordance, HIV seroconcordance, sexual role and condomless receptive (CRAI) and insertive anal intercourse (CIAI).ResultsOur analysis included 187 young transwomen that reported a total of 464 sexual partnerships where they had at least one episode of anal sex in the past 6 months. We found casual (n=232 or 50%) and commercial partnerships (n=106 or 22.8%) to be significantly associated with a lower odds of CIAI (OR=0.53, 95% CI 0.32 to 0.86 and OR=0.39, 95% CI 0.18 to 0.82) and CRAI (OR=0.30, 95% CI 0.19 to 0.47 and OR=0.35, 95% CI 0.2 to 0.62) compared with main partnerships (n=126 or 27.2%). Additionally, HIV-positive seroconcordant (n=25 or 5.4%, OR=4.05, 95% CI 1.44 to 11.40) and injection-drug using partnerships (n=25 or 5.4%, OR=3.66, 95% CI 1.34 to 9.95) were found to be significantly associated with an increased odds of CIAI among participants compared with HIV-negative seroconcordant (n=330 or 71.1%) and non-using partnerships (n=338 or 72.8%), respectively.ConclusionYoung transwomen, like other populations, engage in condomless sex more often with main than casual and commercial partners, suggesting a need for interventions that address sexual practices with steady main partners.