The Coral Triangle is a global priority for conservation and since the creation of the Coral Triangle Initiative in 2007 it has been a major focus for a multi-lateral conservation partnership uniting the regions six governments. The Coral Triangle (CT) Atlas was developed to provide scientists and managers with the best available data on marine resources in the Coral Triangle. Endorsed as an official supporting tool to the Coral Triangle Initiative, the CT Atlas strives to provide the most accurate information possible to track the success of the conservation efforts of the Initiative. Focusing on marine protected areas and key marine habitats, the CT Atlas tested a process to assess the quality, reliability, and accuracy of different data layers. This article describes the mechanism used to evaluate these layers and to provide accurate data. Results of the preliminary quality control process showed errors in reputable datasets, outdated and missing data, metadata gaps, and a lack of user instructions to interpret layers. It highlighted the need to challenge existing datasets and demonstrated that regional efforts could improve the data available to evaluate the effectiveness of conservation measures. The Coral Triangle Atlas is continuously being updated to be as accurate as possible for reliable analysis."