Abstract Background Nurses, the largest workforce in healthcare, play a central role in health systems. There is a severe global shortage of nurses, which is expected to worsen as a significant portion approaches retirement age. Early retirements can harm care quality and healthcare access, thus significantly impacting public health. Identifying reasons is crucial to prevent this trend. This study examined factors behind nurses’ early retirement intentions. Methods A descriptive qualitative study was conducted in an Irish hospital (July to September 2023) including individual interviews with 10 nurses aged 55 and over. A thematic analysis was conducted collaboratively by three researchers to identify key factors influencing nurses’ intentions to retire early. Results Five main themes emerged: 1) Health concerns, encompassing physical strain and psychological stress, significantly influencing early retirement intentions; 2) Struggling to balance job demands with personal responsibilities such as caring for ageing parents due to inflexible work schedules; 3) Need for more support from senior leaders to address staffing shortages and investment in aging nurses’ career and retirement planning to make staying more desirable and easier; 4) Feelings about nurses’ experience being undervalued in the evolving healthcare; and 5) Facing constant heavy responsibility in guiding new nurses, while simultaneously fearing patient safety risks and encountering generational differences. Conclusions Developing support systems for ageing nurses, encompassing strategies to ease workload strain, enhancing career opportunities, and promoting intergenerational collaboration are critical for reducing early retirement trends and sustaining a resilient healthcare workforce. By implementing tailored approaches, such as flexible scheduling and mentorship programs for ageing nurses, healthcare organisations can promote workforce longevity and enhance public health outcomes through improved care delivery. Key messages • Health challenges and struggles in work-life balance influence early retirement intentions among nurses, urging flexible work arrangements and improved recognition and leadership in healthcare. • To extend work careers, organisations must invest in ageing nurses’ career and retirement planning, value experience, and acknowledge potential challenges and benefits in intergenerational nursing.