What is the Medicare Annual Enrollment Period (AEP)?

Five things: (1) switch from one Medicare Advantage plan to another; (2) drop MA and return to Original Medicare; (3) join MA from Original Medicare; (4) switch from one Part D plan to another; (5) join Part D for the first time (Part D LEP may apply if you're late). What you CAN'T do during AEP: drop Original Medicare, drop Part A, drop Part B, or get a new Medigap policy without underwriting (Medigap has its own rules separate from AEP).

No — that's a common mix-up. Your first chance to enroll in Medicare is your Initial Enrollment Period (IEP), the 7-month window around your 65th birthday (or via SSDI rules if you're under 65). AEP is for people already on Medicare who want to switch their MA or Part D plans for the next year. Confusing AEP with IEP is one of the most common reasons people end up with a Part B late-enrollment penalty.

No — if you don't make a change, you stay enrolled. But you should still read the Annual Notice of Change (ANOC) your plan mailed by Sept 30. The ANOC tells you exactly what's changing for the next year: premium, copays, drug formulary, network. Plans count on people not reading the ANOC. A plan that worked in 2026 might not be the right fit for 2027.

January 1 of the following year. If you make a change between October 15 and December 7, the new coverage takes effect on January 1. If you make multiple changes during AEP, the last change you make is the one that takes effect.

No — they're different windows. AEP runs Oct 15–Dec 7 and is open to everyone with Medicare. MA OEP runs Jan 1–Mar 31 and is only for people already enrolled in a Medicare Advantage plan. MA OEP allows ONE change: switch to a different MA plan, or switch back to Original Medicare with a stand-alone Part D plan. You can't use MA OEP to switch from Original Medicare to MA.

The 5-Star Special Enrollment Period runs December 8 through November 30 each year and lets you switch into a 5-star Medicare Advantage or Part D plan available in your area, once per year, outside of AEP. CMS publishes star ratings every fall. The 5-Star SEP is a way to upgrade if a 5-star plan becomes available where you live, but you can only use it once and only into a plan that has a 5-star rating.

Be careful. Cold-call solicitation about Medicare Advantage and Part D plans is prohibited under CMS's Medicare Communications and Marketing Guidelines (MCMG). If a stranger calls or texts you about Medicare without your permission, that's a violation. Some TV ads and mailers are legitimate but lead-generation-heavy — they're designed to capture you for a sales call, not to give you neutral information. The free, neutral options are Medicare.gov's Plan Finder, your state SHIP, and Chapter Medicare.

Use the Medicare.gov Plan Finder. Enter your specific medications, your preferred pharmacy, and your ZIP code. The tool ranks all Part D plans available to you by total annual cost (premium + deductible + copays for your drugs). Don't pick on premium alone — the formulary tier of YOUR specific drugs is usually what drives total cost. SHIP counselors and Chapter advisors will run Plan Finder with you for free.

That's a personal decision and depends on your health needs, providers, drugs, and budget. AEP is the right window if you're going to do it. But understand the tradeoff: Original Medicare with Medigap and Part D gives you broad provider access nationwide and predictable costs. Medicare Advantage often costs less in premiums and may include extras (dental, vision, hearing, gym memberships) but uses networks, prior authorizations, and yearly out-of-pocket caps that can run into thousands. If you switch from Original to MA and later want to come back, Medigap may require medical underwriting in most states.

If you're already on a Medicare Advantage plan, the MA Open Enrollment Period (Jan 1–Mar 31) gives you one more chance to make ONE change. The 5-Star SEP runs all year (Dec 8–Nov 30) for switching into a 5-star plan. Other Special Enrollment Periods open for specific life events: moving outside your plan's service area, losing Medicaid, qualifying for Extra Help, leaving an institution. None of these is as broad as AEP — mark your calendar.