The complete genome sequence of "Candidatus Puniceispirillum marinum" IMCC1322, the first cultured representative of the SAR116 clade in the Alphaproteobacteria, is reported here. The genome contains genes for proteorhodopsin, aerobic-type carbon monoxide dehydrogenase, dimethylsulfoniopropionate demethylase, and C(1) compound metabolism. The genome information proposes the SAR116 group to be metabolic generalists in ocean nutrient cycling.