The Transportation Worker Identification Credential program is a Transportation Security Administration (TSA) and U.S. Coast Guard initiative in the United States. The TWIC program provides a tamper-resistant biometric credential to maritime workers requiring unescorted access to secure areas of port facilities, outer continental shelf facilities, certain manufacturing facilities, and vessels regulated under the Maritime Transportation Security Act of 2002, or MTSA, and all U.S. Coast Guard credentialed merchant mariners. As of May 2014, there were 2,999,058 people enrolled in the program. Those seeking unescorted access to secure areas aboard affected vessels, and all Coast Guard credentialed merchant mariners, must obtain a TWIC. The new measures were fully implemented on April 15, 2009. To obtain a TWIC, an individual must provide biographic and biometric information such as fingerprints, sit for a digital photograph and successfully pass a security threat assessment conducted by TSA.

The Transportation Security Administration (TSA) is an agency of the United States Department of Homeland Security (DHS) that has authority over the security of transportation systems within, and connecting to, the United States. It was created as a response to the September 11 attacks to improve airport security procedures and consolidate air travel security under a combined federal law enforcement and regulatory agency.