Transseptal puncture (TP) is the technique used to access the left atrium of the heart from the right atrium via the interatrial septum in increasingly common catheter-based procedures such as atrial fibrillation ablation. Through repetition, experienced TP operators develop manual skills to manipulate the transseptal catheter assembly inside the right atrium to their target on the fossa ovalis. New operators currently train on actual patients to develop this skill, resulting in increased risk of dangerous complications. To create low-risk training opportunities for new TP operators, we are developing a Soft Active Transseptal Puncture Simulator (SATPS), designed to match the dynamics, kinetostatics, and visualization of the heart during TP. The SATPS includes three main subsystems: (i) An anatomically accurate soft right atrium, fitted with pneumatic artificial muscles, mimics the dynamics of the heart felt by the operator through the catheter assembly. (ii) A replaceable, puncturable fossa ovalis simulates the tissue properties of the real fossa to provide accurate kinetostatic force feedback during tenting and puncture. (iii) A simulated intracardiac echocardiography environment gives the user live visual feedback representative of an ultrasound monitor during an actual TP procedure. The SATPS is an ongoing project, with validation and design improvements forthcoming.