Quick answer: the Medicare Annual Enrollment Period runs from October 15 to December 7 every year, and any change you make takes effect on January 1. During this window you can switch Medicare Advantage plans, move between Original Medicare and Medicare Advantage, and join, switch or drop a Part D drug plan. A good review takes about an hour: read your plan’s Annual Notice of Change, list your drugs, doctors and pharmacies, compare plans on Medicare Plan Finder using next year’s costs, and confirm your choice before December 7.
Plans change every year. Premiums move, drugs shift between tiers, doctors leave networks and extra benefits come and go. Staying put without checking is still a choice, and it can be an expensive one if your drug suddenly lands on a higher tier or your main doctor stops taking your plan.
This checklist walks through the review in order, from the notice your plan mails in September to the confirmation letter you should keep in January. It is one part of our Medicare guide covering eligibility, enrollment and costs, which explains how the pieces of Medicare fit together.
Dates, limits and rules below come from Medicare.gov, the Centers for Medicare & Medicaid Services (CMS) and the Social Security Administration, checked October 2026. Plan details vary by ZIP code and change every year. This article is general information, not personalized insurance advice; free one-on-one help is available from your State Health Insurance Assistance Program (SHIP).
What the Annual Enrollment Period Is and Who It Applies To
Medicare.gov calls this window Medicare Open Enrollment, and many people know it as the Annual Enrollment Period, or AEP. Both names describe the same dates: October 15 through December 7. Coverage you pick during that window starts January 1 of the following year.
Changes you can make between October 15 and December 7
According to Medicare.gov’s guide to joining a plan, you can do any of the following during open enrollment:
- Switch from Original Medicare to a Medicare Advantage plan.
- Switch from Medicare Advantage back to Original Medicare.
- Move from one Medicare Advantage plan to another, with or without drug coverage.
- Join a Medicare drug plan (Part D), switch to a different one, or drop drug coverage.
If you make more than one enrollment request, the last one you submit before December 7 is generally the one that counts.
What the window does not cover
Medicare Supplement Insurance (Medigap) works on a different schedule. There is no annual Medigap open enrollment period at the federal level. Your best time to buy Medigap is your six-month Medigap Open Enrollment Period, which starts the month you are 65 or older and enrolled in Part B. Outside that period, Medicare.gov explains that insurers in most states can use medical underwriting, which means they may charge more or decline to sell you a policy. A few states have their own rules that make switching easier, so check with your state insurance department or SHIP.
Signing up for Part A or Part B for the first time also follows separate rules: your Initial Enrollment Period around age 65, a Special Enrollment Period if you had job-based coverage, or the General Enrollment Period from January 1 to March 31.
Who should bother reviewing
Anyone with a Medicare Advantage plan or a standalone Part D plan should look at next year’s details, because both kinds of plans renew on a calendar year and can change benefits, costs and networks. People in Original Medicare with a Medigap policy still have a drug plan to check, and they may also want to compare their total costs against Medicare Advantage options in their area, keeping the Medigap re-entry risk above in mind.
Step 1: Read Your Annual Notice of Change
Your plan has to tell you what is changing before the window opens. Medicare Advantage and Part D plans send an Annual Notice of Change (ANOC) each fall, and Medicare.gov says plans must send it by September 30. Many plans also send an Evidence of Coverage, which is the full rulebook for next year.
What to look for in the ANOC
The notice is usually a short table comparing this year with next year. Go line by line and mark anything that moved:
- Monthly premium. A higher plan premium is easy to spot. Remember that Medicare Advantage members also keep paying the Part B premium.
- Deductibles. Check both the medical deductible (if your Advantage plan has one) and the drug deductible.
- Maximum out-of-pocket limit. Every Medicare Advantage plan has a yearly cap on what you pay for covered medical services. A higher cap means more exposure in a bad health year.
- Copays and coinsurance. Look at the services you actually use: primary care, specialists, labs, imaging, outpatient surgery, hospital stays, physical therapy.
- Drug tiers. Find each of your medications in the drug list and note its tier for next year.
- Network. The ANOC may not list every network change, so verify doctors separately (Step 4).
- Extra benefits. Dental, vision, hearing, fitness and over-the-counter allowances can shrink or disappear.
If you did not get one
Call the plan’s member services number on the back of your card and ask for the ANOC and Evidence of Coverage, or look for them on the plan’s website. If your plan is ending next year, you should receive a non-renewal notice instead, which comes with its own Special Enrollment Period. Read it carefully, because it explains your deadline for choosing a replacement.
Step 2: Build Your Personal List Before You Compare
Plan comparisons are only as good as the information you feed into them. Ten minutes of preparation saves a lot of guessing later.
Your prescriptions
Write down every medication you take, with the exact name, strength, dose form and how often you fill it. Include drugs you take only part of the year. Medicare Plan Finder can pull your current drugs if you log in to your Medicare account, but check that the list is complete and correct.
Your doctors, hospitals and pharmacies
List your primary care doctor, every specialist you see, the hospital you would want to use and your regular pharmacy. Add a mail-order pharmacy if you use one. In Medicare Advantage, network rules decide what you pay, and HMO plans generally do not cover non-emergency care outside the network.
Your expected care next year
Think about planned surgeries, ongoing therapy, regular infusions, a new diagnosis or travel. Someone who expects a knee replacement should weigh hospital copays and the out-of-pocket maximum far more heavily than a person who sees a doctor twice a year.
Your budget for the worst case
Premiums are what you pay when nothing goes wrong. The out-of-pocket maximum in Medicare Advantage, and the Part D out-of-pocket threshold for drugs, show what you could pay when a lot goes wrong. Decide which number you could actually handle.
Step 3: Compare Plans on Medicare Plan Finder
The official comparison tool is Medicare Plan Finder on Medicare.gov. It shows every Medicare Advantage and Part D plan available in your ZIP code, with estimated yearly costs based on the drugs and pharmacies you enter.
Use next year’s view
When the new plan year’s data is available in the fall, make sure you are looking at the coming year rather than the current one. A plan that looks cheap for the rest of this year may cost more in January.
Sort by total estimated cost, not premium
The tool can sort by lowest drug and premium costs. A $0 premium plan can still be the expensive option if your drugs sit on high tiers or need a pharmacy outside its preferred network. Look at the estimated annual total, which combines premiums and expected drug costs.
Check the star ratings
CMS rates Medicare Advantage and Part D plans from one to five stars based on quality and member experience. Ratings are one signal among several. Medicare.gov notes that a five-star plan in your area can be joined through a special enrollment period between December 8 and November 30, once per year, so a top-rated plan is not limited to the fall window.
Know the 2027 Part D limits
The Part D benefit has changed a lot in the past few years. For 2026, Medicare.gov lists a maximum Part D deductible of $615 and caps out-of-pocket spending on covered drugs at $2,100. For 2027, Medicare.gov lists a maximum deductible of $700 and an out-of-pocket threshold of $2,400. Once you reach the threshold, you pay nothing more for covered Part D drugs for the rest of that year. Covered insulin costs no more than $35 for a one-month supply. Our explainer on how Part D formularies and drug tiers work goes deeper into tiers, prior authorization and exceptions.
CMS also announced on July 28, 2026 that the national base beneficiary premium will be $41.33 in 2027, up from $38.99 in 2026. That figure is not what you will pay for any particular plan; it is the starting point Medicare uses for calculations such as the Part D late enrollment penalty.
Step 4: Verify Doctors, Pharmacies and Drug Rules Directly
Plan Finder is a starting point, not the final word. Networks change and directories are not always current.
Call the offices
Ask each doctor’s office whether they will be in network with the specific plan you are considering next year, using the plan’s full name. “We take Medicare” does not mean they take every Medicare Advantage plan. For Original Medicare, ask whether they accept Medicare assignment.
Check pharmacy status
Many Part D plans have preferred pharmacies with lower copays. Confirm that your pharmacy is preferred, not just in network, for each plan you are comparing.
Read the drug rules
For each medication, look for prior authorization, step therapy or quantity limits on the plan’s formulary. Any of these can delay a fill. If a drug you need is not covered, you can ask the plan for an exception, but it is easier to choose a plan that already covers it.
Step 5: Weigh Medicare Advantage Against Original Medicare
Open enrollment is the one time each year when anyone can move between Original Medicare and Medicare Advantage without a special reason. That makes it a good moment to ask whether your current path still fits.
Points that favor Original Medicare with Medigap
Original Medicare lets you see any provider in the country that accepts Medicare, with no network and generally no referrals. Paired with a Medigap policy, most of your cost-sharing is covered, so bills are predictable. The trade-off is higher monthly premiums, a separate Part D plan for drugs, and the medical underwriting risk if you try to buy Medigap after your open enrollment period ends.
Points that favor Medicare Advantage
Medicare Advantage plans bundle hospital, medical and usually drug coverage in one card, often with low premiums and extra benefits such as dental or vision allowances. Every plan has an annual out-of-pocket maximum. In exchange, you generally use a network, may need referrals and prior authorization, and pay copays as you go.
Our side-by-side breakdown of Medicare Advantage vs Medigap walks through the decision with questions to ask yourself. If you are leaning toward a change because of dental, vision or hearing benefits, read our guide to what Medicare covers for dental, vision and hearing first, since those benefits vary widely between plans.
A note on switching back
Leaving a Medicare Advantage plan you joined when you first got Medicare, within the first 12 months, can come with a Medigap trial right under federal rules. Outside of those situations, returning to Original Medicare does not guarantee you can buy a Medigap policy. Ask your SHIP counselor before you switch if Medigap matters to you.
Step 6: Check Cost Help You May Qualify For
People with limited income and savings often miss programs that cut their costs sharply.
Extra Help
Extra Help is a federal program that lowers Part D premiums, deductibles and copays. Medicare.gov lists 2026 limits of $23,940 in income and $18,090 in resources for an individual, and $32,460 and $36,100 for a married couple. For 2027, people with Extra Help pay no plan premium or deductible on qualifying plans and no more than $5.80 for each generic and $14.40 for each brand-name drug. You can apply through the Social Security Administration at any time of year.
Medicare Savings Programs
State-run Medicare Savings Programs can pay Part B premiums and, for some people, deductibles and coinsurance. Income and resource limits are set each year, and some states use higher limits than the federal ones. Qualifying for one of these programs also qualifies you for Extra Help automatically.
Income-related premiums
At the other end of the income scale, higher earners pay an income-related monthly adjustment amount on top of Part B and Part D premiums. That surcharge is set by Social Security, not by your plan, so switching plans will not change it. Our guide to Medicare premiums and IRMAA explains the brackets and how to appeal after a life-changing event.
Step 7: Enroll, Confirm and Keep Records
Once you have picked a plan, the actual enrollment takes a few minutes.
Ways to enroll
You can enroll through Medicare Plan Finder, by calling 1-800-MEDICARE (1-800-633-4227, TTY 1-877-486-2048), or directly with the plan through its website or phone line. Joining a new Medicare Advantage or Part D plan automatically ends your old one of the same type when the new coverage starts, so you do not usually need to cancel separately.
Switching from Medicare Advantage to Original Medicare works a little differently. You can call 1-800-MEDICARE or the plan to disenroll, and joining a standalone Part D plan during the window also moves you back to Original Medicare. If you want drug coverage, make sure you join a Part D plan in the same window to avoid a gap and a possible late enrollment penalty.
Watch for confirmation
You should get a confirmation from the new plan, followed by a welcome kit and a new member card before January 1. Keep the confirmation number from your enrollment and write down the date and time of any phone call. If nothing arrives by mid-December, call the plan.
Beware of high-pressure marketing
Medicare.gov reminds people that Medicare will not call you to sell a plan and that you should never give your Medicare number to someone who calls you unsolicited. Plans and agents must follow CMS marketing rules. If something feels wrong, hang up and call 1-800-MEDICARE yourself.
What You Can Still Change After December 7
Missing the deadline does not always lock you in for a full year.
Medicare Advantage Open Enrollment Period
From January 1 through March 31, people already enrolled in a Medicare Advantage plan can make one change: switch to a different Medicare Advantage plan, or drop Medicare Advantage and return to Original Medicare, adding a Part D plan if they want. This window is only for Advantage members; it does not let someone in Original Medicare join an Advantage plan.
Special Enrollment Periods
Certain life events open a Special Enrollment Period, including moving out of your plan’s service area, losing other coverage, moving into or out of a nursing home, qualifying for Extra Help or Medicaid, or your plan leaving Medicare. Medicare.gov lists the full set of situations and how long each window lasts.
Five-star plans
As mentioned above, if a plan with a five-star overall rating is available where you live, you can switch into it once between December 8 and November 30.
A Printable Annual Enrollment Checklist
Use this list each fall. Most people can finish it in an afternoon.
- Find and read your Annual Notice of Change; mark every cost or benefit that changed.
- Write down your drugs (name, dose, frequency), doctors, hospital and pharmacies.
- Note any planned care or new diagnoses for next year.
- Log in to Medicare.gov and open Medicare Plan Finder for next year.
- Enter your drugs and pharmacies; sort by total estimated cost.
- Compare your current plan with two or three alternatives, including Original Medicare if you are in Medicare Advantage.
- Check each plan’s out-of-pocket maximum and drug rules (prior authorization, step therapy, quantity limits).
- Call your doctors and pharmacy to confirm network status for next year.
- Check whether you qualify for Extra Help or a Medicare Savings Program.
- Enroll before December 7, save the confirmation number and watch for your new card.
- In January, fill a prescription early to confirm the new plan works as expected.
| Date | What happens |
|---|---|
| By September 30 | Plans send the Annual Notice of Change |
| October 15 | Open enrollment begins |
| December 7 | Last day to make open enrollment changes |
| January 1 | New coverage starts |
| January 1 to March 31 | Medicare Advantage Open Enrollment Period (Advantage members only) |
| December 8 to November 30 | Five-star Special Enrollment Period, used once |
Where to Get Free, Unbiased Help
Every state has a State Health Insurance Assistance Program funded in part by the federal government. SHIP counselors give free, one-on-one help comparing plans and do not sell insurance. You can find your local office through SHIPhelp.org or by calling 1-800-MEDICARE.
Medicare.gov and the yearly Medicare & You handbook, mailed to people with Medicare each fall, also summarize the plan options in your area. For questions about premiums, IRMAA or Extra Help applications, the Social Security Administration is the right contact. If you are still learning the basics, our plain-English explainer on Medicare Parts A, B, C and D is a good place to start before you compare plans.
Frequently Asked Questions
When is the Medicare Annual Enrollment Period?
It runs from October 15 to December 7 each year, according to Medicare.gov. Changes made during the window take effect on January 1.
Do I have to do anything if I like my current plan?
No. If your plan is continuing next year and you take no action, you are generally renewed automatically. It is still worth reading the Annual Notice of Change, because premiums, drug tiers and networks can change even when the plan name stays the same.
Can I change my Medigap policy during open enrollment?
The October to December window does not apply to Medigap. You can apply for a different Medigap policy at any time, but outside your Medigap Open Enrollment Period insurers in most states can use medical underwriting. Some states have their own switching rules, so ask your state insurance department or SHIP.
What happens if I miss December 7?
If you are in a Medicare Advantage plan, you can make one change from January 1 to March 31. Otherwise you may need to qualify for a Special Enrollment Period or wait for the next open enrollment.
Will switching plans change my Part B premium?
No. The Part B premium is set by law each year, and any income-related surcharge is set by Social Security. Medicare Advantage members keep paying the Part B premium in addition to any plan premium.
Is Medicare Plan Finder accurate?
It uses plan data submitted to CMS and is the official comparison tool, but networks and pharmacy arrangements can change. Confirm doctors and pharmacies directly with the plan before you enroll.
Sources
- Medicare.gov, Joining a plan: open enrollment dates and allowed changes.
- Medicare.gov, Medicare Plan Finder.
- Medicare.gov, Part D costs and the 2026 and 2027 deductible and out-of-pocket limits.
- Medicare.gov, Help with drug costs (Extra Help income and resource limits and 2027 copays).
- CMS, Medicare Part D 2027 National Average Monthly Bid Amount fact sheet (July 28, 2026).
- Social Security Administration, Medicare premiums and Extra Help applications.
- SHIPhelp.org, State Health Insurance Assistance Programs.
