When Is Medicare Open Enrollment? 2026 Dates for 2027 Coverage and What You Can Change

Medicare open enrollment runs from October 15 to December 7, 2026. Any change you make in that window takes effect on January 1, 2027. It is the one time each year when anyone on Medicare can switch between Original Medicare and Medicare Advantage, change Medicare Advantage plans, or change their Part D drug plan, with no reason needed.

We are an independent site and are not affiliated with Medicare, CMS or any insurer. Dates and rules below come from Medicare.gov and CMS.

This year the window matters more than usual. Part D deductibles and out-of-pocket caps are rising, the number of stand-alone drug plans is falling, and some insurers, Humana among them, are dropping Medicare Advantage plans in many counties for 2027. Doing nothing is allowed, but it is a choice too.

Medicare open enrollment at a glance

Question	Answer
When is Medicare open enrollment?	October 15 to December 7, every year
When do changes start?	January 1, 2027
Who can use it?	Anyone who already has Medicare
What can you change?	Original Medicare vs Medicare Advantage, Medicare Advantage plans, Part D plans
Do you have to act?	No. A continuing plan renews automatically
Missed it?	January 1 to March 31 if you are in Medicare Advantage; otherwise a Special Enrollment Period, if you qualify
Where to compare	Medicare.gov Plan Finder, 1-800-MEDICARE, or your local SHIP

Medicare enrollment dates for 2026 to 2027

• By September 30, 2026: your Medicare Advantage or Part D plan sends its Annual Notice of Change (ANOC), listing what changes on January 1.
• October 1, 2026: plans can start marketing 2027 coverage, and the Medicare.gov Plan Finder shows 2027 plans.
• October 15, 2026: open enrollment begins.
• December 7, 2026: open enrollment ends. Changes must be made by this date.
• January 1, 2027: your new coverage starts.
• January 1 to March 31, 2027: the Medicare Advantage Open Enrollment Period, a second, narrower chance for people already in Medicare Advantage.

The dates never move. Medicare open enrollment is October 15 to December 7 every year, even when December 7 falls on a weekend, so it is worth putting both dates in your diary now.

What you can and can’t change during open enrollment

According to Medicare.gov, between October 15 and December 7 you can:

• Switch from Original Medicare to a Medicare Advantage plan, with or without drug coverage.
• Switch from Medicare Advantage back to Original Medicare. Not sure which suits you? See Original Medicare vs Medicare Advantage.
• Change from one Medicare Advantage plan to another.
• Join, switch or drop a Part D drug plan.

The last change counts. If you change your mind and enrol in a different plan before December 7, the most recent choice is the one that starts on January 1.

What open enrollment does not cover

• First-time Medicare sign-up. Part A and Part B have their own windows around your 65th birthday. Our guide to when to sign up for Medicare explains them.
• Guaranteed Medigap. Open enrollment does not give you a right to buy a Medicare Supplement policy. Outside your six-month Medigap open enrollment period and certain guaranteed-issue situations, insurers in most states can use your health history to refuse you or charge more. A few states, such as California and Oregon, have extra annual switching rules.
• Employer and retiree plans. These follow the employer’s own enrollment calendar. Check with the plan before you change anything, because dropping retiree coverage may mean you cannot get it back.

One trap: joining a drug plan can end your Medicare Advantage plan

Joining a new Medicare Advantage plan automatically ends your old one, and joining a new Part D plan ends your old Part D plan. That is usually what you want.

But if you are in a Medicare Advantage plan with drug coverage and you join a stand-alone Part D plan, Medicare will generally disenrol you from Medicare Advantage and move you back to Original Medicare. If that is not your intention, check with the plan or 1-800-MEDICARE before you sign up.

Medicare open enrollment vs other open enrollment periods

Autumn is crowded with deadlines, and each one is for a different kind of coverage:

Enrollment period	Dates	Who it is for
Medicare open enrollment	Oct 15 to Dec 7, 2026	People with Medicare changing Medicare Advantage or Part D
Medicare Advantage open enrollment	Jan 1 to Mar 31, 2027	People already in Medicare Advantage; one change
Medicare General Enrollment Period	Jan 1 to Mar 31, 2027	People who missed signing up for Part A or B
Marketplace (Obamacare) open enrollment	Nov 1, 2026 to Jan 15, 2027 on HealthCare.gov	People under 65 or not on Medicare
Employer open enrollment	Set by your employer, often Nov	Workers and families with job-based plans

If you are on Medicare, the marketplace window does not apply to you. If someone in your household is under 65, our guide to ACA open enrollment 2027 covers their dates and premiums.

What’s changing for 2027

Plans change every January, so this year’s review should start with the figures CMS has already published:

• Part D: the maximum deductible rises from $615 to $700, and the annual out-of-pocket cap rises from $2,100 to $2,400, according to CMS. Our Medicare Part D 2027 guide explains what that means for your drug costs.
• Premiums: CMS projects the average Medicare Advantage premium will fall from $14.37 to about $12, and the average stand-alone Part D premium will rise from $35.09 to about $36. Your own plan may move much more than the average.
• Part B: the 2026 standard premium is $202.90 a month. The 2026 Medicare Trustees Report projects $209.50 for 2027. CMS usually confirms the official figure in November.
• Plans leaving: if your Medicare Advantage plan is not renewing, you will have had a notice by early October and you get extra time to choose. See Medicare Advantage plans leaving in 2027.
• Star ratings: the 2027 ratings are shown in Plan Finder now. Our guide to Medicare Advantage star ratings explains what they measure.

For the full list, see Medicare 2027 changes.

Missed December 7? Your other options

The Medicare Advantage Open Enrollment Period: January 1 to March 31

If you are in a Medicare Advantage plan on January 1, Medicare.gov says you can make one change between January 1 and March 31:

• switch to a different Medicare Advantage plan, with or without drug coverage; or
• drop Medicare Advantage, go back to Original Medicare, and join a stand-alone Part D plan.

The change starts the first day of the month after the plan gets your request. You cannot use this window to move from Original Medicare into Medicare Advantage, or to switch between stand-alone Part D plans.

Special Enrollment Periods

You may be able to change plans at other times of year if your situation qualifies. Common examples include:

• Your plan is ending. You can choose another plan through the last day of February 2027, and you may have a guaranteed right to buy certain Medigap policies.
• You move out of your plan’s service area or to a new area with different plan options.
• You lose other coverage, such as job-based drug coverage.
• You get Extra Help or Medicaid. People with Extra Help can use a monthly Special Enrollment Period to switch to Original Medicare with a stand-alone Part D plan. See Extra Help 2027.
• A 5-star plan is available where you live. You can switch into it once between December 8 and November 30 of the following year.

Illustrative example

Illustrative. Joan is in a Medicare Advantage plan with drug coverage. Her October ANOC shows her heart medicine moving to a higher tier, which would raise her copay from $15 to $47 a month.

• On November 12 she enters her drugs into Plan Finder and finds another plan in her county that keeps her cardiologist and covers the drug at a lower tier. She enrols online, and the new plan starts January 1. Her old plan ends automatically.
• If she had missed December 7, she could still have used the January 1 to March 31 window, because she is in Medicare Advantage. Her new plan would then have started the month after she enrolled, and she would have paid the higher copay until then.

How to review your plan before December 7

1. Read your Annual Notice of Change. Look for changes to the premium, deductible, copays, pharmacy network, provider network and drug list.
2. Check whether your plan is ending. A non-renewal letter means you must choose a new plan or be moved to Original Medicare.
3. List every drug and dose. Enter them in the Plan Finder on Medicare.gov, which estimates each plan’s yearly drug costs.
4. Confirm your doctors and hospitals. Ask each provider directly whether they will be in the plan’s network for 2027.
5. Compare total yearly cost, not just the premium. A $0 premium plan with high copays can cost more than a plan with a premium.
6. Check the star rating, shown in Plan Finder on a scale of 1 to 5 stars.
7. Get free help if you are stuck. Your State Health Insurance Assistance Program (SHIP) gives free, unbiased counselling, and 1-800-MEDICARE (1-800-633-4227) is open 24 hours a day, except some federal holidays.

How to enrol. You can join a plan through Plan Finder on Medicare.gov, by calling 1-800-MEDICARE, or by contacting the plan directly. Keep the confirmation number.

Be wary of cold calls. Medicare.gov says Medicare will not call you uninvited to sell you a plan or ask for your Medicare number. Do not give your Medicare number to anyone who contacts you out of the blue.

If cost is the main worry, check whether you qualify for a Medicare Savings Program, which can pay your Part B premium.

Related reading

• When to sign up for Medicare covers first-time enrollment and late penalties.
• Medigap Plan G vs Plan N compares the two most popular supplement plans.
• Medicare 2027 changes lists the 2027 premiums, Part D limits and key dates.
• Best dental insurance for seniors on Medicare looks at dental options alongside Medicare.
• Social Security COLA 2027 and Medicare explains how the Part B premium affects your benefit.

Sources and notes

• Medicare.gov, “Joining a plan”, “Open Enrollment” and “Special Enrollment Periods”: open enrollment dates, what you can change, the Medicare Advantage Open Enrollment Period and Special Enrollment Periods.
• Medicare.gov, “Medigap guaranteed issue rights”: Medigap open enrollment and guaranteed-issue rights.
• CMS, CY 2027 Part D redesign program instructions and the July 2026 Part D bid announcement: $700 deductible, $2,400 out-of-pocket cap, projected average premiums.
• CMS, “2026 Medicare Parts A & B Premiums and Deductibles”: $202.90 standard Part B premium.
• 2026 Medicare Trustees Report, as reported by MOAA: projected 2027 Part B premium of $209.50. CMS has not yet published the official figure.
• HealthCare.gov, dates and deadlines: marketplace open enrollment dates for 2027 coverage.
• Joan’s example is illustrative; copay figures are invented to show how the rules work.

This article is general information, not legal or benefits advice. Plan availability and costs depend on where you live. Your State Health Insurance Assistance Program (SHIP) offers free, unbiased one-to-one Medicare counselling.