Japanese whiting (Sillago japonica) are a relatively common species that inhabit coastal shallow waters in Japan and are the target species in an important recreational fishery. We isolated eleven candidate microsatellite loci from a small insert genomic DNA library of S. japonica. We screened for polymorphisms in the eleven loci using wild individuals (n = 48) collected from Suounada Sound, in the Seto Inland Sea, Japan. The number of alleles per locus ranged from 6 to 26 with no evidence of linkage disequilibrium. Observed heterozygosity ranged from 0.58 to 0.98 with one locus exhibiting a significant departure from Hardy–Weinberg equilibrium. A test for cross-amplification using the closely related species, Sillago parvisquamis yielded scoreable peaks and a high level of polymorphism in four loci. These polymorphic microsatellites can be used to identify population structure in S. japonica and provide potential markers for the endangered S. parvisquamis.