Medicare Annual Enrollment Period: What Can You Change?

Last Modified: 10/06/2026 | Reviewed by Keith Armbrecht (NPN 634015)

Quick Summary

Medicare’s Annual Enrollment Period, also commonly called Medicare Open Enrollment, runs:

October 15 through December 7

each year.

During this period, Medicare beneficiaries can make changes to Medicare Advantage and Medicare prescription drug coverage for the following year.

Changes generally take effect:

January 1

Key Facts

During October 15–December 7 you can:

  • Join a Medicare Advantage plan
  • Switch Medicare Advantage plans
  • Leave Medicare Advantage and return to Original Medicare
  • Join a standalone Part D drug plan if eligible
  • Switch Part D plans
  • Drop Part D coverage
  • Change Medicare Advantage drug coverage

You generally can’t use this period as a guaranteed Medigap enrollment period.

Original Medicare to Medicare Advantage

If you currently have Original Medicare, you can enroll in a Medicare Advantage plan during this period.

The new plan generally begins January 1.

Medicare Advantage to Another Medicare Advantage Plan

You can change to another Medicare Advantage plan.

Reasons people may switch include:

  • Doctor network changes
  • Prescription formulary changes
  • Premium changes
  • Copay changes
  • Out-of-pocket maximum changes
  • Benefit changes

Medicare Advantage to Original Medicare

You can also leave Medicare Advantage and return to:

Original Medicare Part A + Part B

If you do, consider whether you also need:

Part D

and:

Medigap

But remember:

Returning to Original Medicare doesn’t automatically guarantee you can purchase any Medigap policy you want.

Changing Part D Plans

If you’re in Original Medicare, you can:

  • Join
  • Drop
  • Switch

standalone Medicare drug plans during Open Enrollment.

Review Your Plan Every Year

Your plan can change its:

  • Premium
  • Drug formulary
  • Drug tiers
  • Pharmacy network
  • Doctor network
  • Hospital network
  • Copays
  • Coinsurance
  • Maximum out-of-pocket
  • Extra benefits

Don’t assume next year’s plan is identical to this year’s.

Video Explanation from Keith

Medicare Open Enrollment: What Can You Change?

Keith's Take

I don’t think Medicare Open Enrollment should automatically mean:

“Change your plan.”

It should mean:

“Review your plan.”

If your doctors, medications and costs still look good, staying put may be the right decision.

But you should never assume nothing changed.

I particularly want people checking their prescription drugs, doctors and annual out-of-pocket risk every year.

Keith Armbrecht
Keith Armbrecht
Medicare on Video

Frequently Asked Questions

Q. When is Medicare Annual Enrollment?
A. October 15 through December 7.
Q. When do changes begin?
A. Generally January 1.
Q. Can I switch Medicare Advantage plans?
A. Yes.
Q. Can I return to Original Medicare?
A. Yes.
Q. Can I change Part D plans?
A. Yes.
Q. Can I join Medicare Advantage?
A. Yes, if otherwise eligible.
Q. Is this Medigap Open Enrollment?
A. No.
Q. Does leaving Medicare Advantage guarantee Medigap?
A. Not necessarily.

Official Government Sources

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