This dataset consists of measurements of species type, count and size of mollusc species of the coral reefs in the Philippines. Sampling was conducted over four locations in the Philippine archipelago from 23 March 2012 to 19 June 2012. Data were collected through a field survey conducted by snorkelling and diving along a series of replicate transects from the shallow nearshore reef flat to a depth of 15m on the outer reef slope. The molluscs were counted, identified to species and measured (to gauge population structure and reproductive status). These surveys formed the field component of NERC Discovery Science project "Effects of coral reef habitat degradation and overexploitation on gastropod molluscs at the global centre of marine biodiversity". The project aimed to: Determine whether deteriorating quality of habitats in coral reef ecosystems, resulting from anthropogenic and other impacts, coupled with intensive artisanal fishing pressure, leads to a decline in gastropod mollusc abundance and species richness; Establish the trajectory of species loss in relation to these pressures by contrasting reefs within regions that have been degraded and/or exploited to differing extents. NERC Research Grant NE/I015566/1 funded the project. The grant is held by the University of York, Department of Environment and led by Dr Julie Patricia Hawkins. It ran from 01 September 2011 to 31 August 2012. Mollusc size and count data have been received by BODC as raw files and will be processed and quality controlled using in-house BODC procedures before being made available online in the future. Raw files are available on request from BODC Enquiries.