For the many millions of migrants, mobility creates vulnerabilities and elevates risk for sexually transmitted infections (STIs). We document, among Tanzanian agricultural plantation residents, migrant characteristics and test associations between migrant status and prevalent STI (HSV-2, syphilis, and HIV). From 623 plantation resident participants, we limit this analysis to participants about whom we know migration status (migrants n = 242, non-migrants n = 291). We collected behavioral data via audio-computer assisted self-interview survey, and clinical data via STI testing. We used multivariate Poisson regression models, stratified by gender and controlling for behavioral risk factors, to measure associations between migrant status and STI. In men, HIV prevalence was 9% for migrants, and 6% for non-migrants. HSV-2 prevalence was 57% for migrants, and 32% for non-migrants. Syphilis prevalence was 12% for migrants, and 3% for non-migrants. Among women, there were few differences in STI prevalence by migrant status: prevalence of HIV was 6% vs. 5% (migrants vs. non-migrants); HSV-2 prevalence was 68% vs. 65%; and syphilis prevalence was 11% vs. 8%. Being a male migrant was significantly associated with increased prevalence of any STI after controlling for sociodemographic and behavioral characteristics (APR = 1.53, 95% CI 1.23–5.25). Migrant women did not have increased prevalence of STI as compared to non-migrant women (APR = 1.03, 95% CI 0.85–1.24). Amongst Tanzanian agricultural workers, male migrants experienced elevated risk for prevalent STI as compared to male non-migrants. We suggest structural interventions to reduce risks associated with migration, especially in male migrants, including workplace-based STI prevention programs, and connecting migrants to resources and support within new communities. The key messages are: migrant men experience significantly elevated risk for prevalent STI, above and beyond sociodemographic and behavioral risk factors, as compared to their non-migrant peers; women in this Tanzanian agricultural plantation community overall had higher prevalence of some STIs than men, migrant women had similar STI risk as non-migrant women; and migration for work, an economic strategy for millions, also creates vulnerabilities, so workplace-based STI prevention programs and connecting migrants to community resources are essential.