Background <p>Pressure ulcers are major patient safety concerns, and bedside nurses’ competencies are central to prevention. Given nurses’ workload in clinical settings, digital education delivery through mobile apps or intranet may be effective. However, direct comparisons between these modalities remain limited. This study aimed to compare mobile application and intranet-based pressure ulcer education for staff nurses and examine effects on knowledge, attitude, and self-efficacy.</p> Methods <p>This randomised controlled trial was conducted in an inpatient nursing department at a general hospital in Seoul, South Korea. Sixty-three ward nurses with at least one year of clinical experience were randomised to the mobile app group (<i>n</i> = 32) or the intranet group (<i>n</i> = 31). One participant assigned to the intranet group did not initiate the allocated education and did not complete the post-intervention assessment. Thus, the complete-case outcome analysis included 62 participants. A four-week pressure ulcer management programme was delivered via mobile app or weekly intranet postings. Knowledge, attitude, and self-efficacy were measured pre- and post-intervention. Difference-in-differences regression analysis assessed group-by-time effects.</p> Results <p>Baseline characteristics and baseline outcome scores were similar between groups. The group-by-time interaction terms were not statistically significant for knowledge (<i>β</i> = 0.31, <i>p</i> = .677), attitude (<i>β</i> = −0.64, <i>p</i> = .554), or self-efficacy (<i>β</i> = 0.57, <i>p</i> = .559), indicating no evidence that pre- to post-intervention changes differed between the mobile app and intranet groups. Descriptively, mean scores increased from baseline to post-intervention in both groups.</p> Conclusions <p>Mobile app-based pressure ulcer education did not demonstrate a statistically significant advantage over intranet-based delivery among experienced staff nurses. Mean scores increased from baseline to post-intervention in both groups, suggesting that structured digital access to the same educational content may support pressure ulcer continuing education in clinical nursing settings.</p> Trial registration <p>Retrospectively registered with the Clinical Research Information Service (CRIS) on January 5, 2026, registration number: KCT0011404 [<a href="https://cris.nih.go.kr/cris/search/detailSearch.do?seq=32007%26search_page=L%26sns_share=Y">https://cris.nih.go.kr/cris/search/detailSearch.do?seq=32007&amp;search_page=L&amp;sns_share=Y</a>].</p>