Medicare Open Enrollment 2026: Dates, What You Can Change, and How to Sign Up for Medicare

Medicare Open Enrollment runs from October 15 to December 7, 2026. Any change you make takes effect on January 1, 2027, as long as the plan gets your request by December 7. If you are happy with your coverage, you don't need to do anything: it renews on its own. This guide covers what you can and can't change, every other enrollment window with its dates, and, if you are about to turn 65, how and when to sign up for Medicare in the first place.

The Short Answer

• October 15 to December 7, 2026: Open Enrollment for 2027 coverage. Switch between Original Medicare and Medicare Advantage, change Advantage plans, or join, switch or drop a Part D drug plan.
• January 1, 2027: any change you made starts. So do your current plan's new costs if you stay put.
• Medigap is not part of Open Enrollment. Outside your one-time 6-month Medigap window, an insurer can usually ask health questions or charge more.
• January 1 to March 31, 2027: people already in a Medicare Advantage plan get one more change.
• Turning 65? Your Initial Enrollment Period is 7 months: 3 before your birthday month, the month itself, and 3 after. Sign up early to have coverage on day one.
• Still working with a job-based plan? You can often delay Part B without penalty, then sign up within 8 months after the job or coverage ends. COBRA and retiree coverage don't count.

Every Medicare Enrollment Window, With Dates

Source: Medicare & You 2027 handbook; Medicare.gov enrollment and Special Enrollment Period pages; 42 CFR 407.25 and 422.62. Calendar dates for 2027 windows follow from the rules.

What You Can and Can't Change in Open Enrollment

Between October 15 and December 7, Medicare.gov says you can:

• Switch from Original Medicare to a Medicare Advantage plan, or from Medicare Advantage back to Original Medicare.
• Join, drop or switch Medicare Advantage plans, with or without drug coverage, or add or drop the drug coverage.
• Join, drop or switch a stand-alone Part D drug plan if you have Original Medicare.

You join a new plan by enrolling in it, through Medicare.gov's Plan Finder, the plan itself, or 1-800-MEDICARE (1-800-633-4227). When you switch drug plans, the old coverage ends when the new one begins, so you don't need to cancel the old plan.

What Open Enrollment does not cover:

• Medigap (Medicare Supplement) policies. Your best time to buy Medigap is your one-time 6-month Medigap Open Enrollment Period. After it, unless you have a guaranteed issue right, an insurer may ask medical questions, charge more, or not sell you a policy at all. Some states give extra rights. So check before you leave an Advantage plan this fall. Our Medigap vs Medicare Advantage guide covers the trade-offs.
• Signing up for Part A or Part B. That runs through Social Security on its own calendar (see How to Sign Up).
• Employer or retiree plans. These follow their own rules. Medicare.gov warns that joining a plan your former employer doesn't offer can cost you your retiree coverage.

Check Your Plan Before December 7

Plans can change premiums, deductibles, drug lists, pharmacies and doctor networks every January. Your plan has to tell you in two documents:

• Annual Notice of Change (ANOC): lists changes to coverage, costs, provider networks and service area starting in January. Plans send it, on paper or electronically, by September 30.
• Evidence of Coverage (EOC): the full rulebook for next year, what is covered and what you pay. Plans send it, or a notice of where to find it, by October 15.

If you didn't get them, call the plan. CMS says Medicare Plan Finder was updated with 2027 plans by October 1, 2026, and 2027 Star Ratings were due on Medicare.gov on or around October 8. CMS projects the average Advantage premium to fall from $14.37 to $12.00 a month in 2027 and the average stand-alone drug plan premium to rise from $35.09 to about $36. Your own plan can differ from the average. Our Medicare Part D 2027 guide has the drug plan details.

Checklist: before December 7, 2026

• Read the Annual Notice of Change. Note the new premium, deductible and out-of-pocket limit.
• Enter every drug you take, with doses, into Plan Finder at Medicare.gov/plan-compare and compare total yearly cost, not just the premium.
• Confirm your doctors, hospitals and pharmacy are in network for 2027.
• Check the plan's 2027 Star Rating.
• If your plan is leaving Medicare, read its letter and decide whether to pick a new plan or move to Original Medicare plus Medigap (see below).
• Before leaving Medicare Advantage, find out whether you can get a Medigap policy and what it costs.
• If you have retiree or union coverage, ask the plan administrator first.
• Make the change by December 7 and keep the confirmation number. For free help, call your State Health Insurance Assistance Program (shiphelp.org).

After December 7: Other Chances to Switch

Medicare Advantage Open Enrollment (January 1 to March 31, 2027). If you are in an Advantage plan on January 1, you can make one change: switch to another Advantage plan, or go back to Original Medicare and join a stand-alone drug plan. The change starts the first of the month after the plan gets your request. You can't use this window to move from Original Medicare into Advantage, or to switch between stand-alone drug plans.

The 5-star Special Enrollment Period. If a Medicare Advantage, drug or Cost plan rated 5 stars is offered where you live, you can switch into it once between December 8, 2026 and November 30, 2027. Watch the drug coverage: moving to a 5-star Advantage plan without drug coverage can leave you with none, and a Part D penalty later.

Life-event Special Enrollment Periods. The common ones, per Medicare.gov:

• You move out of your plan's service area, or to an area with new plan options: from the move through 2 full months after. Tell the plan in advance and it can start the month before.
• You lose employer or union coverage (COBRA included): 2 full months after the month it ends to join a plan.
• You have Medicaid or Extra Help: you can change drug coverage once a calendar month.
• Your plan has been rated below 3 stars for 3 years in a row: you can switch at any time.

If your Medicare Advantage plan is leaving for 2027

If your plan won't renew, coverage ends after December 31, 2026, and the plan will send you a letter. You have three paths:

1. Pick another plan during Open Enrollment (by December 7) so it starts January 1.
2. Use the special right to join another Medicare health plan until the last day of February (February 28, 2027).
3. Do nothing, and you go back to Original Medicare when the plan ends.

The third path comes with a Medigap guaranteed issue right. Medicare.gov says you can apply for a Medigap policy as early as 60 days before your Advantage coverage ends and no later than 63 days after it ends, and in that situation the insurer must sell you the policy, must cover pre-existing conditions, and can't charge more because of your health. The right applies only if you go to Original Medicare, not if you join another Advantage plan, and your state may give more. Add a stand-alone drug plan too.

How to Sign Up for Medicare

If you already get Social Security

You are enrolled automatically. If you started Social Security or Railroad Retirement benefits at least 4 months before turning 65, Part A and Part B start on the first day of your birthday month (or the month before if your birthday falls on the 1st). Your red, white and blue Medicare card arrives in the mail about 3 months before your 65th birthday. If you don't want Part B yet, for example because you have a job-based plan, tell Social Security before the start date on the card. Otherwise you keep it and the premium comes out of your benefit.

If you aren't getting Social Security yet

You have to sign up yourself, with Social Security, not Medicare. Your Initial Enrollment Period is 7 months long: the 3 months before your birthday month, the birthday month, and the 3 months after. A birthday on the 1st shifts the whole window one month earlier.

When coverage starts depends on when you apply:

• In the 3 months before your birthday month: coverage starts the first day of your birthday month.
• In your birthday month or the 3 months after: coverage starts the first day of the month after you sign up.

The second rule dates from January 1, 2023 (42 CFR 407.25). Before that, signing up late in the window could delay coverage by up to 3 months. Applying early still avoids any gap.

Three ways to apply:

• Online at SSA.gov/medicare/sign-up, through a my Social Security account. You can sign up for Parts A and B, or Part A only.
• By phone at 1-800-772-1213 (TTY 1-800-325-0778), weekdays 8 a.m. to 7 p.m.
• At your local Social Security office, by appointment. The Medicare & You handbook suggests contacting Social Security 3 months before you turn 65 to set one up.

Forms you may need: CMS-40B to add Part B during the General Enrollment Period if you already have Part A; CMS-L564, filled out by your employer, to prove job-based coverage when you use the Part B Special Enrollment Period; and CMS-10797 if you missed a window because of an exceptional situation such as a disaster or an employer error. Forms go to your local Social Security office by fax or mail. Railroad workers apply through the Railroad Retirement Board (1-877-772-5772).

Missed your window? The General Enrollment Period

If you missed your Initial Enrollment Period and don't qualify for a Special Enrollment Period, you can sign up for Part B between January 1 and March 31 each year. Coverage starts the first day of the month after you sign up, but you may owe a late penalty for as long as you have Part B.

Do you pay for Part A?

Most people don't. Part A is premium-free if you or your spouse worked about 10 years, or 40 quarters, paying Medicare tax. CMS says that covers about 99% of beneficiaries. Others can buy Part A for $311 or $565 a month in 2026, depending on work history. The standard Part B premium is $202.90 a month in 2026. The 2027 amount had not been announced as of October 11, 2026. Our Part B premium guide has the full cost picture, and higher earners should check the IRMAA brackets.

Turning 65: A Sample Timeline

Hypothetical example: you turn 65 on July 20, 2027 and haven't started Social Security.

Source: Medicare & You 2027; Medicare.gov "How do I sign up for Medicare?"; 42 CFR 407.25(a)(2). Dates are our application of the rules to a sample birthday.

Still Working at 65

If you or your spouse is still working and you are covered by a group health plan from that current job, you can delay Part B without a penalty. You can then sign up:

• at any time while you still have that coverage, or
• during the 8 months that begin the month after the job ends or the coverage ends, whichever comes first.

Coverage usually starts the month after you sign up. If you apply while still covered, or in the first full month after it ends, you can ask for a start date up to 3 months later. Send Social Security form CMS-L564 completed by your employer as proof.

What doesn't count as job-based coverage: COBRA, retiree coverage, VA coverage, Marketplace or other individual plans, and severance coverage. The 8-month clock starts when the job or job-based coverage ends, even if you take COBRA. Medicare.gov's advice is blunt: don't wait for COBRA to end before signing up for Part B.

Employer size matters. At 65, if the employer has 20 or more employees, the job-based plan pays first and Medicare second. With fewer than 20 employees, Medicare pays first (unless the employer is part of a multi-employer plan with 20 or more workers), and the job plan will likely expect you to have Part B before it pays. Ask the benefits office before you skip it.

HSA contributions must stop. You can't put money into a health savings account once you have Medicare. Premium-free Part A starts retroactively up to 6 months before you sign up (but not before 65). If you sign up 6 or more months after turning 65, stop HSA contributions 6 months before you apply, or you may owe a tax penalty. See our health savings account guide and HSA limits.

Drug coverage: if your work plan's drug coverage is creditable (the plan must tell you every year), you can wait to join Part D. Don't go more than 63 days without it. Your Medigap Open Enrollment Period also waits until you take Part B.

Federal and Postal Retirees

FEHB retirees: OPM states the Federal Employees Health Benefits Program has no Part B enrollment requirement. You can keep FEHB with or without Part B. Once you retire, Medicare pays first and FEHB second. Some FEHB plans offer reimbursement for Part B premiums or waive their own cost sharing for Part B services. The usual penalty still applies if you skip Part B and add it later.

Postal Service retirees (PSHB): under the Postal Service Reform Act of 2022, OPM says certain Medicare-eligible postal annuitants and their Medicare-eligible family members must enroll in Part B to stay in a PSHB plan. The exceptions: annuitants who retired on or before January 1, 2025 and weren't already in Part B; employees who were 64 or older on January 1, 2025; and those living outside the U.S. Postal workers near retirement should confirm their status with OPM before turning 65.

Late Enrollment Penalties, With the Math

Source: Medicare & You 2027; Medicare.gov late enrollment penalties; CMS Part D bid fact sheet (July 28, 2026) for the 2027 base premium.

You usually avoid the Part B penalty if you sign up during a Special Enrollment Period or enroll in a Medicare Savings Program. People with Extra Help don't pay the Part D penalty.

Sources & Methodology

• Medicare & You 2027, for Open Enrollment and Advantage Open Enrollment dates, the ANOC and EOC deadlines, Initial and General Enrollment rules, the Part B Special Enrollment Period, the payer chart, HSA timing, penalties and the plan non-renewal rights.
• Medicare.gov: Open Enrollment; Special Enrollment Periods; When can I buy Medigap; Working past 65; How do I sign up; Sign-up forms; Late enrollment penalties.
• Social Security, Sign up for Medicare, for the ways to apply and phone numbers.
• eCFR: 42 CFR 407.25 (when coverage starts), 42 CFR 406.24 and 407.20 (8-month Special Enrollment Period), 42 CFR 422.62 (October 15 to December 7 election period).
• CMS 2027 Medicare Advantage and Part D state fact sheets, for the Plan Finder and Star Ratings dates; CMS press release of September 28, 2026 for projected 2027 premiums; CMS fact sheet of July 28, 2026 for the 2027 Part D base premium.
• OPM, Postal Service Health Benefits and OPM, Medicare for annuitants.

Method notes. The penalty amounts, the timeline and the 2027 calendar dates for rolling windows are our application of the official rules to hypothetical cases. The Part B example uses the 2026 premium because the 2027 premium had not been announced on October 11, 2026. Rules were checked against the primary sources on 2026-10-11.

This article is for general information and is not financial, tax, legal or insurance advice. Wealthy Pot is not affiliated with Medicare, CMS or the Social Security Administration, and we do not sell insurance. Enrollment rules have exceptions for disability, ESRD, Puerto Rico residents and other cases; confirm your own dates with Social Security, 1-800-MEDICARE or your State Health Insurance Assistance Program before acting.

FAQ

When is Medicare Open Enrollment for 2027 coverage?
October 15 to December 7, 2026. Changes take effect January 1, 2027, if the plan gets your request by December 7.

Can I switch Medigap plans during Open Enrollment?
Open Enrollment doesn't cover Medigap. Outside your 6-month Medigap Open Enrollment Period or a guaranteed issue situation, Medicare.gov says you usually won't be able to switch, or may have to answer medical questions and pay more. Some states have extra rules.

How do I sign up for Medicare?
If you already get Social Security, you're enrolled automatically at 65. If not, apply through Social Security online at SSA.gov/medicare/sign-up, by phone at 1-800-772-1213, or at a local office.

When should I sign up for Medicare?
During the 3 months before the month you turn 65, so coverage starts the first day of your birthday month. If you're still working with a large employer's group plan, you may be able to delay Part B.

I'm still working at 65. Do I need Medicare?
You can usually take premium-free Part A and delay Part B if you have group coverage from your or your spouse's current job. With fewer than 20 employees, Medicare pays first, so you likely need Part B. Stop HSA contributions before Medicare starts.

Does COBRA let me delay Part B?
No. COBRA isn't coverage from current work. Your 8-month Part B window starts when the job or job coverage ends, whether or not you take COBRA.

What happens if my Medicare Advantage plan is leaving?
Pick a new plan by December 7, or until the last day of February. If you go back to Original Medicare instead, you have a federal right to buy certain Medigap policies from 60 days before to 63 days after your plan coverage ends.

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"Medicare Open Enrollment 2026: Dates, What You Can Change, and How to Sign Up for Medicare." Wealthy Pot, 2026. https://wealthypot.com/medicare-open-enrollment-2026/