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In marine environments, phylogeographic approaches have the power to counteract the difficulties of studying small, highly mobile organisms that live in a fluid environment. These analyses are particularly useful for studying exploited species, as understanding connectivity and processes governing gene flow between populations is essential to sustainable management of fisheries. Among the most vulnerable of exploited species are marine invertebrates collected for the ornamental aquarium trade, as commercial culture techniques are largely not addressed and vital data on larval biology is inadequate or remain unknown. The Caribbean blue-legged hermit crab (Clibanarius tricolor) is heavily collected for its role as an aquarium cleaner; however, despite its economic and ecological importance, little is known about their population structure or genetic diversity. Here, we investigate the phylogeography and genetic diversity of C. tricolor by comparing structure across four well-defined phytogeographic breaks throughout their range in the Caribbean and west Atlantic: the Florida Straits, Mona Passage, Central America, and central Bahamas breaks. We also explore additional factors (e.g. reproductive strategies, life-history traits, habitat preference, demographic history, biogeographic processes) that may influence whether structure is present in marine organisms within this region. Prior to analyzing structure throughout C. tricolor’s entire range, a preliminary study was done to determine whether high throughput sequencing approaches (i.e. double digest Restriction-site Associated DNA sequencing) were necessary for detecting phylogeographic patterns in C. tricolor. Findings indicated that Sanger sequencing of traditional loci used in decapod studies (mtDNA: cytochrome c oxidase subunit 1, 16S-rDNA; nuDNA: Histone 3) were sufficient for this study. To infer C. tricolor structure and connectivity, analyses investigating genetic diversity (# segregating sites, # haplotypes, nucleotide (p) and haplotype diversity (h)), population structure (TCS haplotype networks, pairwise FST, AMOVA, SAMOVA, Isolation by Distance), and historical demography (neutrality tests, mismatch distribution) were computed. Both mitochondrial and nuclear data were concordant in finding high levels of genetic diversity and connectivity across all populations sampled, failing to reject the null hypothesis of panmixia. Data analysis reveals no evidence for phylogeographic structure across the four hypothesized phylogeographic breaks, supports a demographic expansion ~300,000 ybp, and suggests C. tricolor has a high dispersal potential. Although the nuclear locus was perceived to be more informative than mitochondrial loci, we attributed it to small sample size and low variability. This study revealed the Caribbean blue-legged hermit crab to be a genetically diverse, highly connected, panmictic marine invertebrate. Population structure analyses found no evidence for phylogeographic structure across the four hypothesized phylogeographic breaks, indicating they are not barriers to gene flow for C. tricolor, suggesting high dispersal abilities. Although our data could not identify source and sink populations, our findings suggest C. tricolor is not at risk and is an example of a healthily traded marine invertebrate. Investigations into additional factors that may influence structure suggest that structure is hard to predict. Therefore, studies on poorly studied exploited species would be beneficial, rather than extrapolating from findings from other species as a proxy. This will hopefully provide more foundational data for similar studies in the future.