Medicare Open Enrollment runs from 15 October to 7 December 2026. Anything you change takes effect on 1 January 2027.
The dates are the easy part. The expensive mistake is not picking the wrong plan — it is not looking, because a plan you keep is not the same plan next year.
What automatic renewal actually renews
If you take no action, your coverage generally continues. What continues is the plan, not the terms. Every year a plan may change:
| Premium | What you pay monthly |
| Copays and deductibles | What you pay when you use it |
| Formulary | Which drugs are covered — medications can be dropped or moved to a higher tier |
| Network | Which doctors, hospitals and pharmacies are in it |
So somebody who changes nothing can find in January that a medication they have taken for years is no longer covered, or that their doctor has left the network — and the window to move closed on 7 December.
Watch for the Annual Notice of Change, and open it. Every plan is required to send one before enrollment opens, and it does exactly one job: it lists what is different next year compared with this year. It arrives in a plain envelope among the marketing that plans and brokers send at the same time, which is why it so often goes in the bin with them. If you read one document about your coverage all year, read that one — it is the only item in the post that describes your plan rather than selling you a different one.
How to actually review, in fifteen minutes
- List your medications — names and doses. This is the step that determines everything else.
- Check each one against the plan’s formulary for next year. Covered, and at what tier?
- Check your doctors and your pharmacy are still in network for next year, not this year.
- Then look at the premium. Doing this first is how people end up on a cheap plan that does not cover their prescriptions.
- Compare on medicare.gov, which lets you enter your drugs and see total expected cost rather than premium alone.
Premium is the least useful number
A plan’s advertised premium is the one figure marketing leads with and the one that predicts your annual cost least well.
What you actually pay is premium plus deductible plus copays on the things you use. A plan that is $30 a month cheaper and moves one of your regular medications to a higher tier can cost several hundred dollars more over a year. The comparison that matters is total expected cost for your prescriptions and your doctors.
On the out-of-pocket cap
Part D includes an annual limit on what a member pays out of pocket for covered prescription drugs, which matters most to people with high drug costs.
The exact figure is set for each plan year, so the number to rely on is the one in your own plan documents rather than a figure quoted in an article or an advertisement. It is worth confirming, because for anyone on expensive medication it changes the arithmetic more than any premium difference.
Dates worth writing down
| September | Annual Notice of Change arrives — read it |
| 15 October | Open Enrollment opens |
| 7 December | Open Enrollment closes |
| 1 January 2027 | Changes take effect |
Medicare Open Enrollment runs from 15 October to 7 December 2026, with elections effective 1 January 2027, during which beneficiaries may join, switch or drop Medicare Advantage and Part D prescription drug plans. Plans may change premiums, cost sharing, formularies and provider networks annually and are required to notify members through an Annual Notice of Change issued ahead of the enrollment period. Part D includes an annual out-of-pocket limit for covered prescription drugs; the applicable amount is set for each plan year and members should confirm it in their own plan documents. Dates and programme descriptions are as published by the Centers for Medicare & Medicaid Services and medicare.gov, which are authoritative. This article is general information and not medical, insurance or financial advice; individual circumstances differ and beneficiaries should verify details with medicare.gov, their plan, or a State Health Insurance Assistance Program counsellor.
Frequently Asked Questions (FAQ)
When is Medicare Open Enrollment?
15 October to 7 December 2026. Any change you make takes effect on 1 January 2027.
What can I do during it?
Join, switch or drop a Medicare Advantage plan or a Part D prescription drug plan. It is the main annual opportunity to change those choices.
What happens if I do nothing?
Your current plan generally renews automatically — but with next year’s costs, next year’s drug list and next year’s provider network, which may all differ from this year’s. Doing nothing is a choice to accept those changes unseen.
What is the Annual Notice of Change?
A document your plan sends before enrollment opens, setting out what is changing for the coming year — premiums, copays, covered drugs and network. It is the single most important piece of post you will receive about your coverage.
Is there a cap on prescription costs?
Part D now includes an annual limit on what a member pays out of pocket for covered prescription drugs. The exact figure is set for each plan year, so check the amount stated in your own plan documents rather than relying on a number quoted elsewhere.
What should I check besides the premium?
Whether your specific medications are still on the plan’s formulary, whether your doctors and preferred pharmacy are still in network, and what the copays are for the things you actually use. A lower premium with your drug removed from the formulary is not cheaper.
