If you or a loved one is approaching retirement age or already enrolled in Medicare, you may be asking the all-important question: when is Medicare open enrollment? This time of year can be crucial for reviewing your coverage, adjusting your plan, and making sure your health care needs are met — without overpaying.
Let’s walk through everything you need to know about Medicare open enrollment, including key dates, what changes you can make, and how to avoid common pitfalls. Whether you’re on Original Medicare, considering Medicare Advantage, or adjusting your Part D drug plan, this guide can help.
What is Medicare?
Medicare is a federal health insurance program in the United States primarily for people aged 65 and older. It also covers certain younger individuals with disabilities, including those with end-stage renal disease or amyotrophic lateral sclerosis (ALS). Administered by the Centers for Medicare & Medicaid Services (CMS), Medicare helps cover hospital care, doctor visits, and prescription drugs.
Medicare is divided into four parts and covers various different things:
- Medicare Part A: Hospital, skilled nursing, hospice
- Medicare Part B: Outpatient and preventive care
- Medicare Part C: Also known as Medicare Advantage, which combines Parts A and B (and often D) into a private plan
- Medicare Part D: Prescription drug coverage
So, when is Medicare open enrollment?
The Medicare Annual Enrollment Period (AEP) runs from October 15 to December 7 each year. Any changes you make during this time will go into effect on January 1 of the following year.
During this window, you can:
- Switch from Original Medicare to a Medicare Advantage plan (Part C)
- Switch back to Original Medicare from an Advantage plan
- Change from one Advantage plan to another
- Join, drop, or change your Part D prescription drug plan
This period is specifically for individuals already enrolled in Medicare. If you’re turning 65 or qualifying for Medicare for the first time, you’ll likely be using a different enrollment period — like the Initial Enrollment Period or a Special Enrollment Period.
What should you review during Medicare open enrollment?
Just because you were happy with your plan last year doesn’t mean it’s still the best fit. Insurance companies can (and do) make changes every year.
Here’s what to check:
1. Your ANOC letter
This “Annual Notice of Change” arrives each fall and outlines any changes to your plan — including premiums, deductibles, and coverage.
2. Your provider network
Are your doctors and specialists still in-network for 2025?
3. Your prescription drug list
Have your medications changed? Have your drugs moved tiers or been removed from your current plan’s formulary?
4. Your total costs
Premiums, co-pays, and out-of-pocket maximums can shift each year. Check the total cost of your care — not just the monthly Medicare premium.
5. Your pharmacy
Some plans offer discounts at preferred pharmacies or mail-order options.
Why Does Medicare Open Enrollment Matter?
Medicare is a huge program: in 2022 alone, it covered more than 65 million Americans and paid out over $900 billion in health care benefits.
But here’s the truth: Medicare doesn’t cover 100% of your health expenses. That’s why reviewing your plan matters. You may need a Medicare Supplement (Medigap) policy or want to compare Part C plans that offer extra benefits like dental or vision.
Failing to review your plan could leave you with higher costs, surprise bills, or coverage that no longer meets your needs.
How Do I Avoid Medicare Open Enrollment Scams?
Unfortunately, scam calls spike during open enrollment. Remember:
- Medicare will never call you to sell a plan.
- Don’t give out your Medicare number unless you initiated the call.
- Watch out for high-pressure sales tactics or “free” offers that seem too good to be true.
You can report suspected Medicare scams at ReportFraud.ftc.gov.
Need Help Reviewing Your Medicare plan?
Choosing the right plan isn’t just about checking boxes; it’s about understanding your unique health needs and budget. At Senior Insurance Solutions, we help Medicare beneficiaries in Colorado feel confident and informed.
We’ll walk you through your options, compare available plans, and make sure you’re set up for the year ahead. There’s no cost to you for our help.
Schedule your no-cost Medicare plan review today, and make the most of open enrollment while it’s here.
Frequently Asked Questions About Medicare Plans
When is Medicare Open Enrollment for 2025?
The Medicare Open Enrollment Period occurs every year from October 15 to December 7. Any changes you make take effect on January 1 of the following year. This timing is the same nationwide and applies to people already enrolled in Medicare.
What changes can I make during open enrollment?
During this period, you can:
- Switch from Original Medicare to a Medicare Advantage plan (Part C)
- Switch from Medicare Advantage back to Original Medicare
- Change from one Medicare Advantage plan to another
- Join, drop, or switch your Medicare Part D prescription drug plan
Is open enrollment the same as the initial enrollment period?
No. Your Initial Enrollment Period (IEP) happens when you first become eligible for Medicare — usually around your 65th birthday or when you qualify due to disability. Open enrollment is only for people already on Medicare who want to adjust their coverage for the upcoming year.
Can I change Medigap (Medicare Supplement) plans during open enrollment?
Not always. Medigap plans have their own enrollment window, which starts when you’re 65 or older and enrolled in Part B. During this six-month Medigap Open Enrollment Period, you typically have guaranteed issue rights. After that window, changing Medigap plans may require medical underwriting.
What happens if I miss the Medicare open enrollment period?
If you miss the October 15–December 7 window, you generally must wait until next year unless you qualify for a Special Enrollment Period (SEP) due to specific life changes (moving out of your plan’s service area, losing employer coverage, Medicaid changes, etc.). Missing the window could leave you stuck with a plan that no longer fits your needs.
Does Medicare open enrollment affect my doctors or medications?
It can. Many Medicare Advantage and Part D plans update provider networks and drug formularies each year. That means your doctor might become out-of-network or your medication could change tiers — impacting your costs. Reviewing your plan during open enrollment helps prevent surprises.
