SIX features Jackie Ortiz, a lesbian SEAL, depicted with dignity and competence. Her sexual orientation is presented as a normal aspect of her life, with her relationship shown without prejudice or conflict. The series portrays her as a respected team member, contributing to an implicitly affirming and respectful representation of an LGBTQ+ character within a military drama.

Christianity is generally portrayed as a source of personal strength, comfort, and moral guidance for several U.S. Navy SEAL characters and their families. The narrative treats these expressions of faith with respect, showing how characters grapple with their beliefs amidst the challenges of war.

The primary depiction of Islam in the series is through the actions and ideology of the extremist group Boko Haram, who serve as the main antagonists. Their interpretation of Islam is presented as a justification for violence, oppression, and fanaticism, without significant counterbalancing portrayals of mainstream or positive Islamic practices.