When a child turns 26, they age out of a parent's Federal Employees Health Benefits (FEHB) or Postal Service Health Benefits (PSHB) plan, requiring the parent to notify their agency. The child receives 31 days of free coverage to allow conversion to a guaranteed-issue policy (which often has fewer benefits and higher costs). A common alternative is Temporary Continuation of Coverage (TCC), available for up to 36 months at full premium plus a 2% administrative fee, with enrollment requests due within 60 days of the child's 26th birthday.
Read more: https://www.govexec.com/pay-benefits/2025/10/what-know-when-your-child-ages-out-federal-health-coverage/408854/