Shipping and Mailing

Can I mail CUI?

CUI information and material may be transmitted via first class mail, parcel post, or bulk shipments with in-transit automated tracking and accountability tools where available.

When mailing CUI material or sending through interoffice or interagency mail, the sender must place a CUI cover sheet on top of documents and all material will be placed in an opaque envelope without CUI markings on the outermost layer. 

An opaque envelope or container is one that cannot be seen through.