With heart disease increasing worldwide, demand for new minimally invasive techniques and transcatheter technologies to treat structural heart disease is rising. Cardioscopy has long been considered desirable, as it allows direct tissue visualization and intervention to deliver therapy via a closed chest, with real-time fiber-optic imaging of intracardiac structures. Herein, the feasibility of the advanced cardioscopic platform, allowing both transapical and fully percutaneous access is reported. The latter technique, in particular, is believed to represent a milestone in the development of the cardioscope. Cardioscope prototypes were used in 7 bovine models (77.2-101.1 kg) for transapical or percutaneous insertion. Miniature custom-built, water-sealed cameras (diameters: Storz, 7 Fr; Medigus, 1.2 mm) were used. For percutaneous cardiopulmonary bypass, the pulmonary artery was occluded by a balloon catheter (Intraclude, 10.5 Fr, 100 cm) and perfused with a crystalloid solution. Cameras were inserted transapically (n = 4) through the left ventricular apex or percutaneously (n = 5) via the carotid artery. Insertion of the optimized cardioscope devices was feasible via either approach. Intracardiac structures (left ventricle, mitral valve opening/closure, chordal apparatus, aortic valve leaflets, and regurgitation) were visualized clearly and without deformation. Catheter tips were successfully bent >180° inside the left ventricle; rotation and navigation to view various intracardiac structures were feasible in all cases. This study showed the technical feasibility of direct cardioscopic visualization using transapical and percutaneous approaches. This advanced cardioscopic instrumentarium represents a promising platform for future interventions and surgery under direct visualization of the beating heart.