TDYs

Temporary duty, commonly called TDY, is a period of official travel away from a service member's permanent duty station to perform a mission or task. TDY is used by military services, government agencies, and some large private-sector organizations to conduct business without a permanent relocation.

Durations vary widely, from a few days to several months; many assignments last one to four weeks, but longer deployments are possible for training, exercises, or audits. Common purposes include training, conferences, inspections, site surveys, and operations.

TDY orders authorize the travel and establish official status. Travel is funded by the employing agency; individuals are typically entitled to per diem, lodging, transportation, and related subsistence allowances. In the U.S. DoD and federal government, per diem and travel allowances are governed by the Joint Travel Regulations (JTR) or Federal Travel Regulation (FTR) and applicable agency supplements.

Logistics include making travel arrangements, obtaining orders, handling accommodations, and submitting expense reimbursements. Personnel generally must maintain records of daily activities or mission justification as required.

TDY is distinct from a permanent change of station (PCS), which involves relocation of residence and reassignment. Some branches also use related terms such as temporary additional duty (TAD) in certain contexts.

Policy considerations address health, safety, and security, and may influence family and personal life for longer assignments; agencies may provide support services or itineraries to minimize disruption.