Halocynthia aurantium (Stolidobranchia: Pyuridae) is a species of tunicate of commercial value that is commonly found in the northern Pacific Ocean and in the Bering Sea. Here, we determined the complete mitogenome of sea peach H. aurantium using 150 PE high-throughput sequencing. The assembled mitogenome is 14,979?bp in length (overall A?+?T contents 56.2%), and contains 13 protein-coding genes, 21 transfer RNAs, two ribosomal RNAs. Phylogenetic analysis of the mitogenome sequence of H. aurantium fully resolved it in a clade with H. roretzi. These data and results will be useful for future studies on the evolution of the Halocynthia and the Pyuridae.