We examined whether hormonal contraception (HC) use predicts sexual frequency throughout and across young women's intimate relationships. From 2008-2012, the Relationships Dynamics and Social Life Study collected weekly surveys over 2.5 years, and included 893 women (aged 18-19 at baseline) who reported 2,547 intimate relationships across 32,736 weeks. Three-level logistic multilevel models assessed the weekly probability of sexual intercourse based on 1) weekly HC use (vs. nonuse) and 2) duration of HC use, both accounting for several relational and individual characteristics, including relationship duration. Women had more frequent sexual intercourse when they were using HC than when they were not (predicted probabilities .65 vs .41). The weekly probability of sexual intercourse increased sharply within the first month of HC initiation (by about 27 percentage points), remained high for several months, then began to slowly decline (yet remained above that of nonuse). When separated by method type, similar trajectories were found for the pill, ring, and IUD/implant; following the initial increase, steeper declines in intercourse frequency were found for the contraceptive injectable, eventually dropping below pre-initiation levels. Findings signify the immediate influence of reduced pregnancy fears in facilitating sexual intercourse among young women, which may decline as HC use continues long-term.