Abstract Purpose Aorto-left ventricular tunnel (ALVT) is an extremely rare, albeit prenatally detectable, extracardiac channel that connects the ascending aorta to the cavity of the left ventricle. Materials and Methods All ALVTs diagnosed prenatally (2006–2020) in five tertiary referral centers were retrospectively assessed for prenatal ultrasound findings, intrauterine course, postnatal outcome, and surgical treatment. We focused on the size of the tunnel and alterations of perfusion of the left ventricular outflow tract and aortic arch. Results 11 fetuses were diagnosed with ALVT at a mean gestational age of 24.8 weeks. All cases were associated with severe dilatation of the left ventricle and a to-and-fro flow in the left outflow tract. Signs of congestive heart failure were present in five fetuses, four of which were terminated and one of which died in the neonatal period. One fetus died in utero at 34 weeks without prior signs of cardiac failure. Of the five survivors, two underwent the Ross procedure. In both cases the prenatal left ventricular outflow was exclusively via a large tunnel. The remaining three neonates underwent patch closure of the tunnel. In these cases, the prenatal outflow of the left ventricle was via the aortic valve and simultaneously over the tunnel. Conclusion Prenatal diagnosis of ALVT should be considered in the presence of left ventricular hypertrophy, dilatation of the aortic root, and to-and-fro flow in the aortic outflow tract. Signs of heart failure are associated with an unfavorable outcome. Large tunnels, particularly in combination with the absence of flow over the aortic valve, may be an unfavorable predictor of surgical repair.