Treatment strategies in paediatric pulmonary arterial hypertension (PAH) have evolved over the last years, but survival is still poor. Recently, in adults with severe PAH, upfront triple combination therapy (uTCT) from diagnosis has been reported to show significant clinical improvement and excellent long-term outcome. This retrospective, observational study aimed to assess the efficacy of uTCT in paediatric PAH.Children diagnosed with PAH between 2010 and 2019 and started with uTCT were included. World Health Organization Functional Class (WHO-FC), haemodynamics, echocardiography, six-minute walking distance, and serum level of N-terminal-Pro-Brain-Natriuretic-Peptide were assessed at baseline, after three and 6 months and at last available follow-up. Events were defined as death, lung transplantation or Potts shunt.Twenty-one children (median age 4.8 years (2.5-12.8), 57% females) were included. All children except one were in WHO-FC III or IV (28% and 67%, respectively). After 3 months, one child had died and one child had received a Potts shunt. The remaining 19 children showed clinical and echocardiographic improvement, which persisted at 6 months. Children with idiopathic and heritable PAH showed one-, two-, and three-year transplant-free survival estimates of 100%, 94%, and 87%, albeit 47% of them receiving a Potts shunt during follow-up.Children with severe PAH, but not pulmonary veno-occlusive disease, improved significantly with uTCT and showed beneficial up to 3-year survival rates, albeit 47% of them receiving a Potts shunt during follow-up. The role of a Potts shunt in conjunction to uTCT in paediatric PAH needs to be further established.