Background: Adults with congenital heart disease (ACHD) are a growing population needing ongoing care. The aim of this study was to investigate if a dedicated ACHD team impacted the timing and indication of invasive cardiology procedures in these patients at our hospital. Methods: Our retrospective single-center study enrolled adult patients with moderate or complex congenital heart disease and with at least one cardiac catheterization between January 2010 and December 2021. According to the period, procedures were labeled as group A (2010 to 2015) or group B (2016 to 2021) and further divided into diagnostic (DCC) and interventional cardiac catheterizations (ICC). Results: 594 patients were eligible for the study. Both DCC (p < 0.05) and ICC increased between groups A and B (p < 0.05). In group B: Fontan patients accounted for the majority of DCC (p < 0.001), while DCC decreased in arterial switch repair (p < 0.001). In Fontan patients, conduit stenting was prevalent (p < 0.001), while fenestration closures dropped (p < 0.01). In patients with tetralogy of Fallot and native outflow tract, percutaneous pulmonary valve implantations (PPVI) increased, with a concurrent reduction in pulmonary valve replacements (p < 0.001 vs. surgical series). In right ventricular conduits, ICC increased (p < 0.01), mainly due to PPVI. Among Mustard/Senning patients, baffle stenting increased from Group A to Group B (p < 0.001). In patients with pulmonary atresia and biventricular repair, ICC often increased for pulmonary artery stenting. Conclusions: A dedicated working group could improve ACHD patients’ indications for interventional procedures, leading to tailored treatment, better risk stratification and optimizing time until heart transplantation.