Medicare Open Enrollment 2026: What KFF's Guide Explains

Medicare's Annual Enrollment Window Runs Through December 7, 2026

Medicare's annual Open Enrollment Period runs from October 15 to December 7, 2026, giving the program's roughly 68 million beneficiaries about eight weeks to review and change how they get their coverage for 2027. A brief published October 9, 2026 by KFF, a nonprofit health policy research and news organization formerly known as the Kaiser Family Foundation, walks through the key questions beneficiaries ask during this window: what can be changed, who is affected, and how the choices compare. This article summarizes KFF's explainer at the original brief and adds practical guidance for readers weighing their options before the deadline.

During this period, people enrolled in Medicare can switch from Original Medicare to a Medicare Advantage plan, move from Medicare Advantage back to Original Medicare, change from one Medicare Advantage plan to another, or switch Part D prescription drug plans. Any change made during this window takes effect January 1, 2027. Beneficiaries who take no action stay in their current plan, which is why KFF's brief stresses reviewing plan materials even for people who feel satisfied with their current coverage.

Why Reviewing Coverage Every Year Matters

Medicare Advantage and Part D plans can change their premiums, deductibles, drug formularies, and provider networks from one year to the next, even when the plan name stays the same. According to KFF's brief, this is one of the main reasons the annual enrollment period exists: it gives beneficiaries a yearly checkpoint to confirm their current plan still fits their health needs and budget before new terms take effect. A plan that covered a specific medication at a low copay in 2026 may adjust that drug's tier or remove it from the formulary for 2027, and a preferred doctor or hospital may move in or out of network.

KFF's brief also distinguishes Open Enrollment from the separate Medicare Advantage Open Enrollment Period, which runs January 1 through March 31 each year. That later window is narrower: it lets people already enrolled in a Medicare Advantage plan switch to a different Medicare Advantage plan or move to Original Medicare, but it does not allow a switch from Original Medicare into Medicare Advantage, and it is not available to people enrolled only in Original Medicare.

How to Compare Plans Before December 7

KFF's brief points beneficiaries to Medicare's official Plan Finder tool at Medicare.gov as the primary resource for comparing Original Medicare, Medicare Advantage, and Part D options side by side using current premiums, deductibles, and drug costs. Readers working through that comparison this year should check a short list of specifics rather than relying on last year's notes:

• Confirm whether current prescriptions are still covered and at what tier, since formularies reset annually.
• Check whether a preferred primary care doctor, specialist, or hospital is still in network for 2027.
• Compare total annual cost, not just the monthly premium, including deductibles and expected out of pocket drug spending.
• Read the Annual Notice of Change mailed by the current plan, which lists what is different for 2027.

Beneficiaries who want help working through these questions can call 1-800-MEDICARE, use the Plan Finder at Medicare.gov, or contact their State Health Insurance Assistance Program (SHIP) for free, unbiased counseling. A licensed insurance agent can also walk through specific plan options, though readers should confirm any agent is licensed in their state and ask how the agent is compensated before enrolling.

Who This Affects and What to Watch Next

The open enrollment period applies to anyone already enrolled in Medicare, not to people newly becoming eligible, who instead use their own Initial Enrollment Period tied to turning 65 or qualifying through disability. For current beneficiaries, the main risk of skipping this year's review is staying on autopilot in a plan whose costs, network, or drug coverage shifted for 2027 without the person noticing until a claim is denied or a pharmacy bill is higher than expected.

Senior Plan Path's view: treat the October 15 to December 7, 2026 window as a required annual check, not an optional one, even for beneficiaries planning to keep their current plan. Reading the Annual Notice of Change, checking drug formularies, and confirming network status takes less time than resolving a coverage gap discovered in February. Readers who want a deeper walkthrough of plan types and deadlines can read KFF's full brief using the link at the top of this article.