Losing or Leaving Employer Health Coverage
You may enroll in Original Medicare (Parts A and B) up to 8 months after your employment or employer health insurance ends, whichever comes first. This is true if you are covered under your spouse's employer coverage, as well. You may also qualify for a Special Enrollment Period (SEP) to enroll in Original Medicare while your employer coverage is still active.
You can enroll in a Medicare Advantage (Part C) or prescription drug (Part D) plan up to two months after your employment or employer health insurance ends. Otherwise, you can switch your coverage during Medicare Open Enrollment, October 15 through December 7.
COBRA and retiree health plans are not considered employer health coverage. You are not eligible for this SEP when COBRA coverage ends. However, you may be eligible for a different SEP.