Patent foramen ovale (PFO) is a frequent condition which carries a significant risk for stroke when associated with deep venous thrombosis and primary or secondary coagulation abnormalities. Here, we describe a patient in which scuba diving is thought to be associated with stroke in a subject with an otherwise clinically silent PFO. During a rapid ascent a 43-year-old-scuba diver reported weakness and paresthesias in the right arm which lasted about 10 min. He presented similar symptoms 2 days later 1 h after diving, and a third time on his flight back home. The MRI showed multiple hyperintense areas on T2-weighted images in the white matter. Transoesophageal echocardiography (TEE) showed a PFO, whilst all haematological and haemocoagulation tests were negative. Scuba diving may constitute a patho-physiological condition in the presence of PFO as breath-holding promotes right-to-left shunt and arterialization of venous bubbles.