The Batu Feringgi area (N coast, Penang Island), with a high concentration of beach hotels, is critical to the tourist economy of Malaysia. Three large imbricated granite boulders were discovered on the NE end of the beach, at 5°28 51.77?N, 100°15 72?E. These boulders, dipping 45°–70° seaward, are shaped as tabular parallelepipeds with rounded corners, with maximum masses of 1.1–2.4 t, based on a density of 2.71 g/cm3. The boulder shapes were dictated by the presence of joints in the coastal outcrops, which represent an uplifted and exhumed tropically-weathered granite-tor landscape. In order to produce imbrication of several boulders, the mode of transport has to be rolling/overturning, rather than by sliding or saltation. The hydrodynamic equations for the initiation of boulder transport used in this study are the modified Nott equations, from Nandasena et al. (Marine Geology 281:70–84, 2011). Calculations were made using slopes of 2°and 5°. The results of the calculations indicate that the minimum velocities required to transport the boulders under free-rolling transport modes were 6.07 and 6.12 m/s for 2° and 5° slopes respectively. For joint-bounded boulders, the minimum velocities are 9.39 and 9.53 m/s for 2° and 5° slopes respectively. These velocities are higher than the maximum velocities experienced at this particular locality during the great 26 December 2004 Indian Ocean tsunami, the largest known tsunami in recorded history. Because this tsunami flooded the area but did not result in appreciable damage to infrastructure, it is concluded that the imbricated boulders on Batu Feringgi beach are the result of tropical storm activity in the past, rather than from recent or past tsunamis. The N coast of Penang is thus regarded as safe from the hazard of damaging tsunamis resulting from mega-earthquakes in the Sumatra-Andaman subduction zone, but the area is prone to tropical storm damage (with a return frequency of about 1 in 400 years), with wave velocities exceeding 6–9.5 m/s.