Purpose: To measure the impact of hospital-treated self-harm by hanging and drowning in Ireland in 2007-2019 and identify risk factors for these methods of self-harm. Method: Data on all self-harm presentations to Irish hospitals between 2007 and 2019 were obtained from the National Self-Harm Registry Ireland, a national self-harm surveillance system. Multinomial regression was used to explore factors associated with attempted hanging and drowning. Results: The age-standardised incidence rate of attempted hanging and drowning increased by 126% and 45%, respectively, between 2007 and 2019. The incidence of both methods was highest among young people aged 15-24 years. The odds of presenting to hospital for attempted hanging were highest in males (aOR 2.85, 95% CI 2.72-3.00), people experiencing homelessness (aOR 1.32, 95% CI 1.16-1.49) and individuals living in the capital, Dublin (aOR 1.23, 95% CI 1.17-1.29). The odds of presenting for attempted drowning were highest in males (aOR 1.68, 95% CI 1.58-1.78) and people experiencing homelessness (aOR 2.69, 95% CI 2.41-2.99). Conclusion: The incidence of hospital-treated self-harm by hanging and drowning is increasing in Ireland and is highest among adolescents and young adults. Males and people experiencing homelessness may be at highest risk and warrant targeted preventive interventions.