Objective To evaluate the effects of increased access to immediate postpartum contraceptive implants (IPI) on repeat pregnancy and contraceptive use rates among patients with opioid use disorder (OUD). Materials and Methods Between 2016 and 2018, 194 postpartum patients with OUD were offered the option of IPI placement at an institution with limited immediate postpartum long-acting reversible contraception availability and followed for one-year postpartum. Differences in pregnancy rates between participants who did and did not choose IPI were examined using logistic regression with inverse probability of treatment weighting from propensity scores accounting for differences between the two groups. Results Among 194 participants, 96 (49.5%) chose an IPI and 98 (50.5%) chose an alternative method or no contraception (non-IPI). Among IPI participants, 76 (80.9%) continued to use their implant at one-year postpartum. Overall, 19 participants had a repeat pregnancy and 11 (57.9%) were unintended. In multivariable analyses, repeat pregnancy was more likely among those who did not choose IPI (OR 9.90; 95% CI 3.58–27.03) than those who did. Participants with OUD and who used alcohol (11.66; 1.38, 98.20) or cocaine (2.72; 1.23, 5.99) during pregnancy were more likely to choose IPI. Participants who were married (0.28; 0.09, 0.89), engaged in OUD treatment prior to pregnancy (0.48; 0.25, 0.93), and happier when they found out about their pregnancy (0.87; 0.77, 0.98) were less likely to choose IPI. Conclusion Offering patients with OUD the option of IPI is associated with high utilisation and continuation rates, and low rates of repeat pregnancy within one-year postpartum.