Background: This article aimed to examine and compare the frequency of occurrence of a broad range of non-suicidal self-injury (NSSI) behaviours in an international sample of women. Methods: Female participants with NSSI (n = 464) were recruited via a range of websites and completed a questionnaire examining 17 different types of NSSI types and their frequency, severity, and duration. Results: Prevalent acts were cutting, scratching, and word carving; cutting and scratching occurred frequently, whilst word carving most often occurred as a single episode. Analyses revealed significant differences between Australian and U.S. participants, with U.S. participants having significantly higher rates of cutting, wound interference, carving, scratching, and sharp object sticking. Participants also reported on other self-harm methods not assessed by the questionnaire. Conclusions: Word carving may be qualitatively different from other forms of NSSI. More severe NSSI methods (e.g., bone breaking) are less prevalent than less dangerous methods (e.g., scratching). Participants considered a range of indirectly harmful or suicidal behaviours as self-injury contrary to researcher or clinician understanding. Finally, there may be cultural differences in relation to NSSI between countries where such behaviours are common, although further research is required to determine this.