Your Medicare options

The Medicare Annual Enrollment Period

Medicare’s Annual Enrollment Period — also called Open Enrollment — runs every year from October 15 to December 7. It’s the window when anyone with Medicare can change their Medicare Advantage and Part D drug coverage, with changes taking effect January 1.

Reviewed by Scott Stafford, Licensed Insurance Agent

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What the Annual Enrollment Period is

The Annual Enrollment Period — often called Medicare Open Enrollment — runs every year from October 15 to December 7. It’s the one window when anyone with Medicare can freely change their Medicare Advantage and Part D drug coverage, no questions asked. Any change you make takes effect the following January 1.

This is different from your Initial Enrollment Period, which is your one-time window around turning 65. The Annual Enrollment Period comes back every fall, and it exists so you can adjust your coverage as plans — and your own needs — change from year to year.

What you can change

During the Annual Enrollment Period, you can:

  • Switch from Original Medicare to a Medicare Advantage plan, or from Advantage back to Original Medicare.
  • Switch from one Medicare Advantage plan to another.
  • Join a Part D drug plan, switch to a different one, or drop your drug coverage.

One thing the Annual Enrollment Period does not cover is Medicare Supplement (Medigap). Medigap has its own rules and, outside of guaranteed-issue situations, may require medical underwriting — so switching a Supplement is a separate process you can pursue any time of year, not just in the fall.

Don’t confuse the fall Annual Enrollment Period with the Medicare Advantage Open Enrollment Period, which runs January 1 to March 31 and only lets people already in an Advantage plan make one additional change.

How to prepare

By late September, your current plan mails you an Annual Notice of Change. It’s the most important piece of mail you’ll get all year, because plans change every January — premiums, deductibles, drug lists, and provider networks can all shift. Read it before you do anything else.

Then run a quick check: are the drugs you take still on the formulary, and at the same tier? Are your doctors and pharmacy still in network? And what’s the total cost for the year, not just the premium? A plan with a low premium can cost more overall once you add deductibles and copays. With those answers in hand, you can compare the plans available where you live and pick the best fit for the year ahead.

Common mistakes to avoid

A few traps catch people every year:

  • Auto-renewing without checking. Letting a plan roll over is easy, but a plan that fit last year may not fit this one after its annual changes.
  • Choosing on premium alone. The cheapest premium isn’t always the cheapest plan once your drugs and care are factored in.
  • Missing December 7. The deadline is firm. After it, you generally wait until next fall unless you qualify for a Special Enrollment Period.

Common questions

Annual Enrollment Period questions

When is Medicare’s Annual Enrollment Period?
Every year from October 15 to December 7. Changes you make during that window take effect the following January 1.
What can I change during the Annual Enrollment Period?
Your Medicare Advantage and Part D drug coverage — you can switch plans, join, or drop coverage. Medicare Supplement (Medigap) isn’t part of this window and follows its own rules.
What if I miss the December 7 deadline?
You generally have to wait until the next Annual Enrollment Period, unless you qualify for a Special Enrollment Period or, if you’re in an Advantage plan, the January 1 to March 31 Advantage window.

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