Field and laboratory study of egg masses, encapsulated development stages and early-hatched veliger larvae of the sub-Antarctic observations Fusitriton magellanicus (Roding, 1798) are described from samples collected in the Magellan Strait (Santa Ana Point: 53°38'15"S, 70°54'38"W), Chile, between 2005 and 2006. We aimed to determined if: i) if these gastropod shows a reproductive pattern development similar to low-latitude ranellids, and with respect to other sub-Antarctic locations within the Gondwanian distributional range (Australia, New Zealand, South America); ii) if F. magellanicus exhibit similar patterns as other Chilean ranellids; and iii) if F. magellanicus exhibit developmental attributes that define as long-distance broadcasters from cold water. F. magellanicus laid around 125 capsules/egg mass. Each contained an average of 2,789 ± 481 embryos, grouped in one circular arrangement. Mean eggs size was 180 μπι. Encapsulated period lasted between 55 and 67 days at 10°C, and hatched larvae of 245 to 349 μm in shell length. Spawning occur during spring (October to November; 8°C) associated to an increment of freshwater discharge of San Juan River. A comparison of eggs/embryos/larvae abundance between temperate and tropical Ranellidae allow us to predict that Fusitriton magellanicus shows developmental attributes that indicate higher fecundity in relation to Chilean ranellids and that define it as a long-distance broadcaster.