Medicare Open Enrollment vs Annual Enrollment: what's the difference?

The Annual Enrollment Period, October 15 to December 7, is when anyone with Medicare can switch between Original Medicare and Medicare Advantage, change Advantage plans, or join, switch or drop a Part D drug plan, with changes starting January 1. The Medicare Advantage Open Enrollment Period, January 1 to March 31, is only for people already in an Advantage plan, and allows one change: to another Advantage plan or back to Original Medicare.

The confusion is understandable. People call the fall period "open enrollment," and there are several other periods with "open enrollment" in the name, including the one for Medicare Supplements and the one for ACA Marketplace plans. Here's how each one works, with the dates for the 2027 plan year.

The two periods side by side

Sources: NCOA; SelectQuote.

Annual Enrollment Period: October 15 to December 7

This is the big one, often called "fall open enrollment." Every Medicare Advantage and Part D plan can change its premiums, copays, drug lists and networks each January, so this is your yearly chance to make sure your coverage still fits. During AEP you can:

• Switch from Original Medicare to a Medicare Advantage plan, or the reverse
• Switch from one Advantage plan to another, including between HMOs and PPOs
• Join a Part D drug plan, switch to a different one, or drop drug coverage

If you make more than one change, the last one you make by December 7 is the one that takes effect on January 1. If you're happy with your plan and it's still offered, you don't need to do anything; it renews automatically.

Before AEP: the Annual Notice of Change

By the end of September, your Advantage or Part D plan mails you an Annual Notice of Change (ANOC) explaining what's different next year. Plans can start marketing next year's coverage on October 1, so early October is the time to compare, even though you can't enroll until October 15. Read your ANOC for:

• Premium and deductible changes
• Drugs moving tiers or leaving the formulary
• Doctors or hospitals leaving the network
• Changes to dental, vision, hearing and allowance benefits
• A notice that your plan is ending or leaving your county

For 2027, Part D costs are rising (deductible up to $700, out-of-pocket cap $2,400) and many Advantage plans are trimming extras, so this year's ANOC deserves a careful read. See 2027 Part D changes.

How to review your plan during Annual Enrollment

1. Check your doctors and hospitals against the plan's 2027 network, not this year's.
2. Re-price every prescription at your pharmacy, using the 2027 drug list.
3. Compare total yearly cost: premium, copays and the out-of-pocket maximum, not just the premium.
4. Check extra benefits you actually use, such as dental, vision and hearing.
5. Look at star ratings, and whether the plan is new or has a track record.
6. Decide by early December, so there's time to fix any enrollment problems before the deadline.

Medicare Advantage Open Enrollment: January 1 to March 31

This period is a second chance for people who are already in a Medicare Advantage plan. If your new plan isn't working out, perhaps a doctor you expected isn't in network or a drug costs more than you thought, you can make one change:

• Switch to a different Medicare Advantage plan, with or without drug coverage, or
• Drop your Advantage plan, return to Original Medicare, and join a stand-alone Part D plan

You can't use it to move from Original Medicare into Advantage, or to switch stand-alone Part D plans if you have Original Medicare. People who are new to Medicare and join an Advantage plan also get this one-change window during their first three months with the plan.

The catch when leaving Advantage

Returning to Original Medicare during MA Open Enrollment is allowed, but a Medicare Supplement isn't guaranteed. Outside your six-month Medigap window at 65 and a few guaranteed-issue situations, Supplement companies can ask health questions and decline you. Florida doesn't have a yearly guaranteed right to switch into Medigap. If you joined Advantage when you first became eligible at 65 and it's within 12 months, your trial right usually lets you buy a Supplement with no health questions. Medigap vs Medicare Advantage explains the trade-off.

The other "open enrollments" people mix up

See the turning-65 timeline and signing up while still working for the first-time windows.

Special Enrollment Periods: changes outside these dates

Certain life events let you change plans at other times of year:

• Moving to a new county or state, including moving to or from Florida
• Losing employer or union coverage
• Getting, changing or losing Medicaid or Extra Help
• Your plan leaving your area or ending its contract with Medicare
• Moving into or out of a nursing home
• Switching into a plan rated 5 stars, once a year
• A government-declared emergency or disaster, such as a hurricane, that kept you from making a change on time

Your Medicare calendar for the 2027 plan year

A Florida note

In South Florida, a few things make these periods especially important. Broward and Palm Beach each have more than 80 Advantage plans, so plan changes every year affect many people. Hurricane season runs into late November, overlapping Annual Enrollment; if a declared disaster stops you from enrolling, ask about a disaster special enrollment period. And if your plan leaves Broward or Palm Beach for 2027, you'll get a special enrollment period and may gain a guaranteed right to buy certain Medicare Supplements.

Two example situations

A 70-year-old in Hollywood reads her Annual Notice of Change in September and sees her cardiologist is leaving her plan's network for 2027. During Annual Enrollment she switches to a plan that includes him, effective January 1.

A 68-year-old in West Palm Beach switched to a new Advantage plan in the fall, but in February learns his rheumatology drug is on a much higher tier. During Medicare Advantage Open Enrollment he makes one switch to a plan that covers it better, effective March 1.

What we do for our clients every fall

Every year before December 7, we contact each client to review their plan. We compare the 2027 version of their current plan against the other plans we offer in their ZIP code, re-check their doctors, hospitals and prescriptions, and show them the total yearly cost of each option. If their plan still fits, we tell them to keep it. If something better fits, we help them switch. It's the same process whether you joined us this year or years ago, and it costs nothing.

Common enrollment mistakes

• Not reading the Annual Notice of Change and letting a plan renew with a dropped doctor or drug.
• Waiting until December 6 and rushing a decision.
• Assuming MA Open Enrollment lets you join Advantage from Original Medicare. It doesn't.
• Dropping Advantage in the spring without confirming you can get a Medicare Supplement.
• Confusing ACA Marketplace ads with Medicare enrollment.

We review every client's plan each fall before December 7, at no cost, in English or Haitian Creole. Compare 2027 Medicare Advantage plans in Broward and Palm Beach.