BACKGROUND: Long-acting reversible contraception is more effective for pregnancy prevention than shorter-acting contraceptive methods and has the potential to reduce healthcare disparities and costs. However, long-acting reversible contraception is underused in the United States. One population of interest is beneficiaries of the United States military healthcare system who have access to universal healthcare, including no-cost, no-copay contraception with unlimited method switching, and comprise a large, actual use cohort. Efforts to increase long-acting reversible contraception initiation and continuation in this population may improve health outcomes and mitigate the profound consequences of unintended or mistimed pregnancy on readiness and cost to the military. OBJECTIVE: We aimed to determine long-acting reversible contraception initiation and continuation rates among the diverse population with universal healthcare who are enrolled in the US military healthcare system. STUDY DESIGN: This study is a retrospective cohort of >1.7 million women, aged 14-40 years, who were enrolled in the US military healthcare system, TRICARE Prime, between October 2009 and September 2014. Individuals were assessed for long-acting reversible contraception initiation and continuation with the use of medical billing records. Method continuation and factors that were associated with early method discontinuation were evaluated with the Kaplan-Meier estimator and Cox proportional hazard models. RESULTS: During the study dates, 188,533 women initiated long-acting reversible contraception. Of these, 74.6% women selected intrauterine contraceptives. Method initiation rates remained relatively stable (41.7-50.1/1000 women/year) for intrauterine methods, although the rate for subdermal implants increased from 6.1-23.0/1000 women/year. In analysis of women who selected intrauterine contraceptives, 61.2% continued their method at 36 months, and 48.8% continued at 60 months. Among women who selected the implant, 32.0% continued their method at 36 months; however, 45.8% continued until 33 months (ie, 3 months before the currently recommended expiration date). Compared with intrauterine contraceptive users, implant users were more likely to discontinue their method during the 36 months after insertion (hazard ratio, 1.59; 95% confidence interval, 1.56-1.62; P < .001). Adolescents aged 14-19 years were the least likely age group to discontinue the implant before 36 months; women aged 35-40 years were the least likely to discontinue an intrauterine contraceptive before 60 months. In multivariable analysis that controlled for demographic factors and contraceptive type, early contraceptive method discontinuation was most likely among women aged 20-24 years, implant users, and women with method initiation in military clinics. CONCLUSION: In the US military healthcare system, TRICARE Prime, the initiation of long-acting reversible contraception is low but increasing, and continuation rates are high. This evidence supports long-acting reversible contraception as first-line recommendations for women of all ages who seek contraception.