In modern maritime transportation contracts, contractual carriers rarely perform all the transportation tasks by themselves, and they carry out most of the transportation tasks using performance assistants. Various efforts have been made to protect maritime carrier's performance assistants, especially independent contractors, which include insertion of so-called Himalaya clause in bills of lading or establishing international maritime conventions or national maritime laws with so-called Himalaya clauses. But, except the contractual terms, international conventions or national maritime laws are still hesitant to extend the defenses or limitation of liability of maritime carriers to independent contractors. They have only allowed servants or agents of carriers to avail themselves of the defenses and limitation of liability of carriers. This theses is to study why international maritime conventions or national maritime laws have distinguished servants or agents of carriers from independent contractors and is to recommend to extend carrier's defenses and limitation of liability to independent contractors in maritime and port sectors. The criteria to distinguish servants or agents from independent contractors, where both are performance assistants of carriers, seem to have been whether the carrier can interfere with, control, or supervise the performance of the assistants or whether the performance assistants are to be employed by the carriers or the cargo interests. But as transportation environment has been changed, new criteria should be studied and adopted. To provide new criteria for the performance assistants to be protected by allowing them of the defenses and limitation of liabilities of carriers, the concept of "maritime performing party" of the Rotterdam Rules has been studied. A maritime performing party is a performance assistant of a carrier, who performs the contract of carriage in maritime sectors including loading and discharging ports and includes not only the carrier's servant or agent, but also independent contractors such as actual carriers, stevedore and terminal operators. A maritime performing party can take advantage of a carrier's defenses and limitation of liability, but they are directly responsible to the shipper jointly with the carrier. From the concept of a maritime performing party, new criteria to be adopted can be derived. Those should not be the possibility of interference by the carrier with the performance of the assistants, as in the past, but should be the performance activity section, the nature of the job, or the existence of the carrier's request. Then a theory of legislation for Korean Commercial Act to protect the performance assistants of the maritime carriers including the independent contractors are suggested, using the new criteria.