Abstract Background Left atrial appendage (LAA) thrombus is a contraindication for LAA closure (LAAC). However, in selected cases, oral anticoagulants are strictly contraindicated because of a history of life-threatening bleeding, and LAAC remains the only possible therapy to avoid systemic and especially cerebral embolization. Case summary We report a case of LAAC despite a massive proximal thrombus in a patient who had an absolute contraindication to anticoagulant therapy, with thorough pre-planning using CT-scan, device modeling and thrombus trapping techniques to reduce the risk of systemic embolic events and perform LAAC safely. Discussion Although LAAC remains at high risk in this setting, the use of cautious techniques and tools, from pre-procedure planning to systemic embolization prevention systems associated to a precise TEE-guiding throughout the procedure, allows it to be performed as safely as possible when no other option is available.