Quick Answer: The Medicare Annual Enrollment Period (AEP) runs October 15 to December 7, 2026. During this window, any Medicare beneficiary can switch from Original Medicare to Medicare Advantage (or back), change Medicare Advantage plans, join or change a Part D prescription drug plan, or drop drug coverage entirely. Any change you make takes effect January 1, 2027. If you do nothing, your current plan auto-renews -- but the plan's benefits may have changed, so reviewing your options every year is worth the time.
The Medicare AEP is the main annual opportunity for the roughly 68 million Americans on Medicare to review and adjust their coverage. Plans change every year -- premiums go up, drug formularies shift, and networks narrow or expand. A plan that was right for you last year may cost hundreds more in 2027 if you do not compare. The 2026 Part B standard premium is $202.90 per month and the national average Part D premium is $34.50 per month, but your Medicare Advantage or Part D plan premium on top of those numbers is set by the private insurer and can change each October.
This page covers exactly what you can change during the 2026 AEP, how to compare options on medicare.gov, the one major catch when switching from Medicare Advantage back to Original Medicare (Medigap underwriting), and the three mistakes that cost people the most money. For beneficiaries approaching 65 for the first time, see our Medicare eligibility page, which covers the separate 7-month Initial Enrollment Period.
6 Steps to Get Coverage
Common Mistakes That Cost People Thousands
The most expensive mistakes Medicare beneficiaries make during AEP:
- Skipping the ANOC and auto-renewing without comparing. Plan premiums and drug formularies change every year. A quick review on medicare.gov Plan Finder can reveal a plan with the same drugs for hundreds less per year.
- Dropping Medicare Advantage without first getting a Medigap quote. In most states, Medigap insurers can deny you based on pre-existing conditions when you switch from Advantage back to Original Medicare -- leaving you with Original Medicare alone and no supplemental coverage.
- Choosing a plan by premium alone and ignoring drug costs. A Part D or Advantage plan with a $0 premium can cost $2,000 more per year than a $50/mo plan if your drugs are on a higher formulary tier.
- Missing the Part D late enrollment penalty window. If you are on Original Medicare without creditable drug coverage for 63 or more consecutive days after becoming eligible, you accrue a permanent penalty of 1% of $38.99 per uncovered month -- for life.
- Not verifying your pharmacy is in-network for the new plan. Switching plans can change your pharmacy from preferred to out-of-network, significantly raising your drug copays on January 1.
Frequently Asked Questions
What are the 2026 Medicare AEP dates?
The 2026 Medicare Annual Enrollment Period runs from October 15 to December 7, 2026. This is the same window every year. Any plan change you make during this period takes effect January 1, 2027. Call 1-800-MEDICARE or visit medicare.gov to enroll or compare plans.
What can I change during the 2026 Medicare AEP?
During AEP you can: switch from Original Medicare to Medicare Advantage or vice versa, change between Medicare Advantage plans, join a Part D prescription drug plan, switch Part D plans, or drop Part D coverage. You cannot use AEP to buy or change a Medigap supplemental policy -- Medigap has separate enrollment rules.
When do my AEP changes take effect?
All changes made during the October 15 to December 7 AEP window take effect January 1, 2027, regardless of when during the window you enroll. If you enroll on October 15 or December 6, your new coverage still starts January 1.
What if I miss the December 7, 2026 AEP deadline?
If you miss AEP, you are generally locked into your current plan for all of 2027. Exceptions: you qualify for a Special Enrollment Period (SEP) due to a qualifying event such as moving out of your plan's service area, losing other creditable coverage, or qualifying for Extra Help. Call 1-800-MEDICARE to check if a SEP applies to you.
Can I switch from Medicare Advantage back to Original Medicare during AEP?
Yes, you can switch back to Original Medicare during AEP. However, unless you qualify for guaranteed-issue rights (generally only within 12 months of first joining Medicare Advantage), Medigap insurers in most states can apply medical underwriting and deny your application or charge more. Get a Medigap quote before you disenroll from your Advantage plan.
Is there a Medicare Advantage Open Enrollment Period in 2027?
Yes. The Medicare Advantage Open Enrollment Period (OEP) runs January 1 to March 31 each year. During the 2027 OEP you can switch from one Medicare Advantage plan to another, or switch from Medicare Advantage to Original Medicare (and add a Part D plan). You cannot use the OEP to switch from Original Medicare to a Medicare Advantage plan.
What is the 2026 Part D late enrollment penalty?
The Part D late enrollment penalty is 1% of the national base beneficiary premium ($38.99 in 2026) for each full month you went without Part D or creditable drug coverage after becoming eligible. The penalty is added permanently to your Part D premium. Avoid it by enrolling in a Part D plan when you first become eligible, even if you take few medications.
Do I need to do anything if I am happy with my current plan?
Not necessarily. Plans auto-renew. But you should still read your ANOC (Annual Notice of Change), which your plan must mail by September 30. If your premium, drug costs, or network changed, you may want to switch. Using the medicare.gov Plan Finder to do a quick comparison takes about 15 minutes and can save hundreds of dollars per year.
