This study assessed the Zanzibar sea cucumber fishery using a multidisciplinary approach.Data was collected by (i) interviewing various groups of actors in the fishery andreviewing management documentation and legislation, (ii) by monitoring catches and (iii)through a visual census of coastal sea cucumber populations in areas open and closed tofishing. The fishery showed clear signs of being unsustainable with high fishing effort,and weak formal and informal management institutions. The fishery operation wascharacterised by an intricate cross-scale structure with both fishers and sea cucumberproducts being transported across national borders. The visual census of commercial seacucumber stocks at three sites open to fishing around Zanzibar showed low densities acrossthe range of sea cucumber value groups including low value species. Furthermore, thediversity of commercial sea cucumber species was lower in fished reefs than on a protectedreef. The poor status of the sea cucumber populations was confirmed by the perception ofan overfished resource by the interviewed actors active in the fishery. This was alsodepicted by the paucity of high value species, and high representation of low value andnewly commercialised species in fishers catch. We conclude that the current state ofZanzibar’s sea cucumber populations is compromising the fisheries self-replenishment andexistence and that the fishery is in urgent need of a complete management reform.