In women's rugby, players regularly interchange between the rugby sevens (R7) and rugby union (RU) formats. Yet, the game demands and particularly the physical aspects respective to both formats vary and players must be able to respond accordingly. The aim of this study was to compare peak running demands in R7 and RU players. A total of 51 international women players participated. HSBC World Sevens Series (n = 19) and Six Nations Rugby Union tournament matches (n = 10) were analyzed for a total of 437 individual match observations. Global positioning systems were utilized to measure total (in meters) and high-speed (above 16km·h-1, in meters) distance and frequency of accelerations (above 2.5m·s-2, n) during different rolling-average periods (1-7min) to obtain peak running activity values. Power law modeling was used to obtain slope and intercept. For all variables, peak values and the value at the 90th percentile (P90) were analyzed. No intercept difference (P = .25; -0.12 ± 0.17) was observed between formats for total distance (161 vs 155m·min-1). In contrast, R7 players reported a higher intercept (P = .01; -0.29 ± 0.17) for high-speed distance (66 vs 51m·min-1), while the intercept was higher (P = .01; 0.31 ± 0.20) in RU for accelerations performed (6.1 vs 5.4n·min-1). Regarding P90, higher values (P < .001) were observed in R7 for total and high-speed distance and accelerations. While peak overall intensity was similar, P90 on the high-speed spectrum was higher in R7. Information on the most demanding match-play periods specific to both women's rugby formats can inform training specificity by tailoring sessions to ensure sufficient exposure to these peak demands and, consequently, aid transitioning betweenformats.