Do Physician NPI numbers expire?
The National Provider Identifier (NPI) is an Administrative Simplification Standard under the Health Insurance Portability and Accountability Act (HIPAA).

For covered health care providers, the NPI is a unique identifying number. In the administrative and financial transactions required by HIPAA, covered health care providers, all health plans, and health care clearinghouses must use NPIs. The NPI is a ten-position numeric identification that is devoid of intelligence. This means that the numbers do not carry other information about healthcare providers, such as the state in which they live or their medical specialty.

HIPAA Rules for NPI
In the administrative and financial transactions required by HIPAA, covered healthcare providers, all health plans, and healthcare clearinghouses must use NPIs.
As outlined in the Federal Regulation, The Health Insurance Portability and Accountability Act of 1996 (HIPAA), covered providers must also share their NPI with other providers, health plans, clearinghouses, and any entity that may need it for billing purposes.
Where can you look up NPIs?
There are many websites that help you do NPI number lookup. Below we have listed few websites.

Do NPI numbers expires?
No, NPI numbers for physicians do not expire. An NPI is assigned to a physician and stays with him for the rest of his life. You’ll only be able to get a replacement NPI under exceptional situations (I.e., fraudulent use).