Artisanal fisheries continue to be vital for food security and sustainability, employment, and economic well-being in Tanzania's coastal communities. However, underreporting has plagued these fisheries for decades, stemming from fragmented data collection systems, geographic challenges, reporting species to family level (not species level) and inadequate inclusion of all fishing methods, including spot fishing targeting tuna species. This paper explores the necessity of reconstructing the missing catch data from artisanal fisheries in Tanzania, underscoring historical and structural factors that have led to consistent underreporting. We stress the importance of comprehensive and harmonised data collection and management for adherence to national, regional and international obligations and regional conservation and management efforts. The paper highlights the implications of improved data reporting to the Indian Ocean Tuna Commission (IOTC) and the Food and Agriculture Organization of the United Nations (FAO) and the benefits of addressing data gaps for sustainable fisheries management in Tanzania