We sought to describe the use and outcomes of small, medium and large premounted stents in patients with congenital heart disease, including incidence of and risk factors for re-intervention and development of in-stent stenosis. Premounted stents offer several advantages over traditional manually crimped bare-metal stents, especially in small patients. There are no data describing the medium-term effectiveness and outcomes of premounted stents in congenital heart disease. We performed a single-center retrospective review of all small, medium and large premounted stents implanted over an 8-year period. Premounted stents were implanted in 71 vessels within 59 patients with a 97 % success rate. Regardless of implantation site, premounted stent implantation resulted in significant improvements in vessel size and pressure gradient (p < 0.0001). Over a median follow-up duration of 3.1 years [interquartile range (IQR) 1.3–5.2], 25 patients (43 %) required re-intervention (18 catheter based, 3 surgical and 4 hybrid) at a median time of 1.4 years (IQR 0.9–3.0) from implant. Factors associated with re-intervention included age ≤1.9 years [hazard ratio (HR) 2.4, p = 0.03], weight ≤11.5 kg (HR 2.5, p = 0.03) and bare-metal premounted stents compared to covered premounted stents (HR 4.2, p = 0.001). In-stent stenosis was diagnosed in 42 % of premounted stents which underwent follow-up angiography. No identified characteristics were associated with in-stent stenosis, including “oversizing” the premounted stent. Small, medium and large premounted stents are effective in treating vascular stenosis in congenital heart disease. Frequent follow-up is required, especially in smaller patients with expected somatic growth, and to evaluate for in-stent stenosis which occurs in nearly half of premounted stents.