A set of single nucleotide polymorphisms (SNP) was developed from the transcriptome of 10 individuals of the sea rose Pentapora fascialis (Cheilostomata) collected in Banyuls-sur-Mer Bay (NW Mediterranean sea). 53042 putative SNPs were identified and mapped on a de novo assembled transcriptome. A selected set of 320 SNPs with highest coverage and uniquely mapped in the assembled transcriptome was tested using a MassARRAY System on 95 individuals sampled in natural rocks and artificial reefs distributed over a hundred kilometers in the NW Mediterranean (outisde Banyuls-sur-Mer Bay). A total of 177 SNPs were successfully genotyped and found to be polymorphic. Among these, 154 SNPs were in Hardy-Weinberg equilibrium over all samples, with significant linkage disequilibrium in only 21 pairs of SNPs. The newly developed loci will be a valuable tool for population genetics studies of this calcifying bryozoan species whose erect structure makes it an engineering species and a target for conservation plans.