The Medicare Annual Enrollment Period (AEP) runs from October 15 through December 7 each year. During this window, you can switch from Original Medicare to Medicare Advantage (or vice versa), change Medicare Advantage plans, add or drop Part D prescription drug coverage, or adjust your existing plan. Changes you submit by December 7 take effect January 1 of the following year.

The December 7 deadline is firm. If you miss it, you will be locked into your current coverage for the entire next calendar year unless you qualify for a Special Enrollment Period. According to the Centers for Medicare & Medicaid Services, millions of Medicare beneficiaries use this annual window to review their options and make adjustments based on changing health needs, medication costs, and plan changes (Medicare, 2026).

Use this checklist to review your coverage, compare plans, and submit any changes before the December 7 cutoff.

Review Your Current Coverage and Costs

Start by gathering your current plan documents, including your Summary of Benefits, Evidence of Coverage, and the Annual Notice of Change (ANOC) your plan mailed in late September. The ANOC details what is changing for the upcoming year, such as premium increases, cost-sharing adjustments, formulary updates, or network changes.

Check your total out-of-pocket spending for the current year. Add up premiums, deductibles, copays, and coinsurance. If your costs were higher or lower than expected, that signals whether your current plan still fits your needs or if a different plan might save you money next year.

Compare Prescription Drug Coverage (Part D)

If you take prescription medications, review your Part D drug plan’s formulary for the upcoming year. Plans regularly adjust which drugs they cover and which tier each medication falls into. A medication that was covered as a Tier 2 generic this year might move to Tier 3 or even be dropped from the formulary entirely next year.

Use the Medicare Plan Finder at Medicare.gov to enter your current medications and compare Part D plans available in your area. The tool shows each plan’s estimated annual cost based on your specific prescriptions, including premiums, deductibles, and copays at each coverage stage (Medicare Plan Compare, 2026).

If you are in the Part D coverage gap (the “donut hole”), compare plans carefully. Some plans offer better gap coverage than others, which can mean hundreds or thousands of dollars in savings if you take expensive medications.

Verify Your Doctors and Hospitals Are In-Network

For Medicare Advantage plans, provider networks change every year. Confirm that your primary care physician, specialists, and preferred hospitals are still in-network for 2027. Call the plan directly or check the online provider directory, and verify with your doctor’s office that they plan to remain in the network.

If your doctor is leaving the network, you have two options: switch to a Medicare Advantage plan that includes your doctor, or switch to Original Medicare (Parts A and B), which allows you to see any provider that accepts Medicare assignment nationwide.

Evaluate Medicare Advantage vs. Original Medicare

Medicare Advantage (Part C) bundles hospital coverage (Part A), medical coverage (Part B), and usually prescription drug coverage (Part D) into one plan, often with extra benefits like dental, vision, or hearing. However, these plans use networks and require referrals for specialists in many cases.

Original Medicare (Parts A and B) offers broader provider access with no network restrictions, but it does not include prescription drug coverage unless you add a standalone Part D plan. Most people on Original Medicare also purchase a Medigap (Medicare Supplement) policy to cover copays, coinsurance, and deductibles.

If your health needs have changed, or if you value nationwide provider access over lower premiums, the Annual Enrollment Period is the time to switch between these coverage models. Foundational health coverage principles, as covered in texts such as Principles of Public Health, emphasize matching coverage structure to individual medical needs and financial capacity.

Check for Extra Benefits and Plan Star Ratings

Medicare Advantage plans compete on extra benefits. For 2027, many plans are offering gym memberships, over-the-counter allowances, telehealth, meal delivery after hospital discharge, and transportation to medical appointments. Review what each plan includes and whether those benefits are ones you will actually use.

Also check the plan’s Star Rating, which Medicare assigns on a scale of 1 to 5 stars based on quality and performance. Plans with 4 or 5 stars generally offer better customer service, care coordination, and health outcomes. Higher-rated plans may also qualify for additional enrollment periods.

Consider Medigap if You Are on Original Medicare

If you are on Original Medicare and do not have a Medigap policy, the Annual Enrollment Period does not apply to Medigap. Medigap has its own enrollment rules, and in most states you have a guaranteed-issue right to buy Medigap only during your Medigap Open Enrollment Period (the six months starting the month you turn 65 and are enrolled in Part B).

However, if you are switching from Medicare Advantage back to Original Medicare during AEP, you should apply for a Medigap policy at the same time. Be aware that insurers can deny Medigap applications or charge higher premiums based on health history if you apply outside your guaranteed-issue period.

Submit Your Enrollment or Plan Change by December 7

Once you have compared plans and decided on a change, submit your enrollment through one of these methods:

  • Online at Medicare.gov using the Plan Finder tool.
  • By phone at 1-800-MEDICARE (1-800-633-4227), available 24/7.
  • Directly through the insurance company offering the plan.
  • Through a licensed insurance agent or State Health Insurance Assistance Program (SHIP) counselor.

Do not wait until December 7. Submit your enrollment a few days early to avoid last-minute technical issues, mail delays, or processing backlogs. You should receive a confirmation letter from your new plan within a few weeks.

Common Mistakes to Avoid

Do not assume your current plan’s costs and coverage will stay the same. Plans change every year, and a plan that was a good value this year might not be next year.

Do not ignore the Annual Notice of Change. This document tells you exactly what is changing, and missing those details can lead to surprise costs or loss of coverage for your medications or providers.

Do not drop your current coverage before your new plan starts. If you disenroll from your current plan before January 1, you could have a gap in coverage. Your new plan takes effect January 1, so keep your current coverage active through December 31.

Frequently Asked Questions

Can I change my Medicare coverage outside the Annual Enrollment Period?

Only if you qualify for a Special Enrollment Period. Common qualifying events include moving to a new address outside your plan’s service area, losing employer coverage, or qualifying for Medicaid or Extra Help. The Medicare Advantage Open Enrollment Period (January 1 through March 31) allows one additional plan change if you are already enrolled in Medicare Advantage.

What happens if I miss the December 7 deadline?

You will be locked into your current coverage for all of 2027 unless you qualify for a Special Enrollment Period. If you are unhappy with your plan, you will not be able to change it until the next Annual Enrollment Period.

Do I need to re-enroll every year?

No. If you do nothing, your current coverage continues automatically for the next year. However, you should still review your plan each year because costs, coverage, and networks change.

Conclusion

The December 7 Medicare enrollment deadline is absolute. Use the days remaining to review your current plan’s Annual Notice of Change, compare Part D drug costs, verify your providers are in-network, and weigh Medicare Advantage against Original Medicare based on your current health needs. Submit any plan changes a few days before the deadline to avoid processing delays.

This article provides educational information about Medicare coverage options and enrollment deadlines. It is not personalized insurance, legal, or financial advice. Medicare plan rules, costs, and availability vary by location and individual circumstances. Confirm current plan details, eligibility, and enrollment procedures with Medicare.gov, a licensed insurance agent, or your State Health Insurance Assistance Program (SHIP) before making coverage decisions.