There are relatively few recorded instances of terrorism at sea, or insurgencies with signi cant maritime con ict. The GTD database gives a gure of just 323 maritime terrorist incidents over the years 1971-2015. Such macro level analysis can lead to an impression that maritime terrorism and insurgency are only niche threats. One expert in this vein, while pointing to the growing potential for maritime terrorism, admitted, so far...its the dog thats not barked. This paper argues such inferences are mistaken. A broader picture emerges if we ask how important is the sea as a logistical conduit for terrorist and insurgency organisations? Access to the sea is often of strategic signi cance in insurgencies or terror campaigns. This paper proceeds via analysis of two discrete case studies where sea logistics have proven transformational to insurgencies or terror campaigns; PIRA and Hezbollah/Hamas weapons smuggling at sea. It is argued that while terror/insurgent movements can gain arms from many sources, sea smuggling of heavier weapons by such groups represents an underrated threat with challenging implications for joint maritime security responses.