Exhibit 21 SUBSIDIARIES OF HORNBECK-LEEVAC MARINE SERVICES, INC. <Table> <Caption> STATE OF SUBSIDIARY NAME INCORPORATION NAME DOING BUSINESS AS Hornbeck Offshore Services, LLC Delaware Hornbeck Offshore Services, LLC HORNBECK-LEEVAC Marine Operators, LLC Delaware HORNBECK-LEEVAC Marine Operators, LLC LEEVAC Marine, LLC Delaware LEEVAC Marine, LLC Energy Services Puerto Rico, LLC Delaware Energy Services Puerto Rico, LLC </Table>