Know When You Can Enroll or Change Coverage
Medicare uses several enrollment periods. The right window depends on your age, current coverage and the change you need to make.
The Medicare enrollment periods to know
Missing an enrollment window can delay coverage or lead to penalties. These are the principal periods, but your personal eligibility and effective date can depend on your circumstances.
Initial Enrollment Period
A seven-month window that generally begins three months before the month you turn 65, includes your birthday month and ends three months afterward.
Annual Enrollment Period
October 15–December 7. You may change Medicare Advantage or Part D coverage for the following year.
Special Enrollment Periods
Certain events—such as losing qualifying employer coverage or moving—may create a separate opportunity to enroll or change plans.
Other important Medicare windows
General Enrollment Period
January 1–March 31 for people who did not enroll in Part A or Part B when first eligible and do not qualify for a Special Enrollment Period.
Medicare Advantage Open Enrollment
January 1–March 31 for people already enrolled in Medicare Advantage. You may switch to another Advantage plan or return to Original Medicare.
Preparing to enroll
Gather your Medicare card, current coverage information, list of doctors, prescriptions and preferred pharmacies. Compare the exact plan documents and confirm the coverage effective date before ending other insurance.
Explore Medicare Advantage, Medicare Supplement, and Part D prescription coverage.
Enrollment-period questions
Is Medicare Annual Enrollment the same as Marketplace Open Enrollment?
No. Medicare and ACA Marketplace coverage use different enrollment periods, eligibility rules and plan systems.
When can I first enroll in Medicare?
Most people first enroll during the seven-month Initial Enrollment Period surrounding the month they turn 65. Different rules can apply if you qualify through disability or ESRD.
Can I change Medicare Advantage plans in January?
If you are already enrolled in Medicare Advantage, the Medicare Advantage Open Enrollment Period runs January 1–March 31.
What if I lose employer coverage?
You may qualify for a Special Enrollment Period. The timing and documentation requirements depend on the coverage you lost, so verify promptly.
Not sure which enrollment window applies?
A licensed Precise Insurance agent can review your timing and help you understand available coverage options.
Precise Insurance Group is not connected with or endorsed by the U.S. government or the federal Medicare program. Enrollment eligibility and effective dates depend on individual circumstances. Verify official rules at Medicare.gov or call 1-800-MEDICARE.