Information checked: 2026-09-10 · Maintenance label: Event-driven
Every autumn, Medicare Advantage and Part D plans send members an Annual Notice of Change describing what will be different in January. Medicare.gov says it arrives in September.
It is the single most useful piece of post you will receive all year, and it is routinely thrown away, because it looks like a renewal notice and reads like a legal document.
This guide covers what to look for in it and how to use it during Open Enrollment, which runs 15 October to 7 December.
Key takeaway
The Annual Notice of Change arrives in September and describes changes taking effect the following January — costs, coverage and service area. Read it against your own prescriptions and doctors, not against the summary page. Open Enrollment runs 15 October to 7 December and coverage begins 1 January. If your notice does not arrive, contact your plan.
Table of contents
- What the notice is
- The autumn calendar
- What to compare, in order
- Then compare against the alternatives
- Frequently asked questions
- Summary
What the notice is
The Annual Notice of Change is sent by your plan and sets out changes to coverage, costs and service area for the coming year. Medicare's own instruction is to review the changes and decide whether the plan will still meet your needs next year.
The framing matters. This is not a renewal confirmation; it is a description of a plan that will be different from the one you signed up for. Doing nothing means accepting every change in it.
If your notice has not arrived, contact your plan directly rather than assuming nothing has changed.
The autumn calendar
| Date | What happens |
|---|---|
| September | Your plan sends the Annual Notice of Change |
| 1 October | Preview next year's plan options on Medicare's Plan Finder |
| 15 October – 7 December | Medicare Open Enrollment — join, drop or switch plans |
| 7 December | In most cases, the last day to change coverage for the next calendar year |
| 1 January | New coverage begins |
| 1 January – 31 March | Medicare Advantage Open Enrollment, for people already in a Medicare Advantage plan |
Two weeks separate the Plan Finder preview on 1 October from the opening of enrolment on 15 October. That is the window to do the comparison properly, before the decision has to be made.
Compare against the alternativesMedicare Plan Finder ›Enter your drugs and pharmacies to see what your current plan and every competing plan will cost next year.What to compare, in order
Work through the notice with your actual prescriptions and your actual doctors in front of you.
- Your drugs. Is each one still covered, and on the same tier? A drug moving up a tier can cost more than the entire premium change.
- Your pharmacy. Is it still a preferred pharmacy? The same drug at a non-preferred pharmacy can cost noticeably more.
- Your doctors and hospitals. Are they still in network for next year?
- Premium and deductible. The headline numbers, and the ones people stop at.
- Copayments and coinsurance for the services you actually use.
- Maximum out-of-pocket, if you are in a Medicare Advantage plan.
- Service area. A plan leaving your county is a decision made for you.
A plan whose premium fell can easily cost you more next year if your medication moved a tier or your specialist left the network. Compare the total for your own use, not the advertised figure.
Then compare against the alternatives
The notice tells you what your current plan is doing. It cannot tell you whether a different plan would do better.
Medicare's Plan Finder lets you enter your drugs and your pharmacies and see estimated annual costs across every plan available where you live. That is the comparison that answers the question.
During Open Enrollment you can join, drop or switch a Medicare Advantage plan, or move between Original Medicare and Medicare Advantage. If you are already in a Medicare Advantage plan and change your mind after January, the 1 January to 31 March window lets you switch to a different Medicare Advantage plan or return to Original Medicare.
Frequently asked questions
When does the Annual Notice of Change arrive?
In September, according to Medicare.gov. It describes changes taking effect the following January.
What if I never received it?
Contact your plan directly. Do not assume that no notice means no changes.
When is Medicare Open Enrollment?
15 October to 7 December. In most cases 7 December is the last day to change coverage for the next calendar year, and new coverage starts 1 January.
What should I check first in the notice?
Your own prescriptions and their tiers, your pharmacy's status, and whether your doctors remain in network. Those change costs more than the premium usually does.
What if I change my mind in January?
If you are in a Medicare Advantage plan, the 1 January to 31 March window lets you switch to another Medicare Advantage plan or go back to Original Medicare.
Summary
The notice arrives in September and describes a plan that will be different in January. Doing nothing accepts every change in it.
Check drugs, tiers, pharmacy and network before premium. Then run the same drug list through the Plan Finder and decide before 7 December.
- Medicare.gov, Plan Annual Notice of Change — That the plan sends the Annual Notice of Change in September and what to do with it
- Medicare.gov, Remember Key Medicare Dates — The 1 October preview date, the 15 October to 7 December Open Enrollment window and the 1 January to 31 March Medicare Advantage window
- Medicare.gov, Joining a plan — What can be changed during Open Enrollment and during the Medicare Advantage Open Enrollment Period