In order to be eligible to be called a RCL “sustainable” tour as of 2020, the tour operator that directly operates the tour must be GSTC Certified. Companies that sub-contract with tour operators to operate RCL tours are recommended to work with their sub-contracted tour operators to encourage and assist them to become GSTC Certified. For companies that sub-contract for some RCL tours but also directly operate some RCL tours, those offices that serve as tour operators should seek GSTC Certification.