How does NCL verify military status for the military discount?

NCL partners with ID.me, our trusted third-party verification service, which uses private and secure data sources to confirm the accuracy of the information you provide. The verification process typically takes five minutes or less. Once your credentials are verified, you will begin seeing your discounted rates on NCL.com at checkout when logged in. The discounted rate displayed at checkout is reflective of the cruise fare discount.

Refer to FAQ https://www.ncl.com/faq/what-should-i-do-if-i-have-issues-enrolling-military-discount if you are having issues.