The 2026 checklist
Checked against Medicare.gov on October 17, 2026. Numbers that change each year say "in 2026".
1. Turning 65: your first sign-up window
7 months: the 3 months before your 65th-birthday month, that month, and the 3 months after
This is your Initial Enrollment Period for Part A and Part B. Sign up in the 3 months before your birthday month and coverage starts the month you turn 65. Sign up in your birthday month or the 3 months after, and it starts the next month. If your birthday is on the 1st, everything moves one month earlier.
If you miss it: you may have to wait for the next sign-up window (item 3) and pay a monthly late penalty for as long as you have Part B.
Source: Medicare.gov · When does Medicare coverage start? · Medicare.gov · When can I sign up for Medicare?
2. Still working at 65 with job coverage: the 8-month window
Any time while you or your spouse still work for that employer, or up to 8 months after the work or the coverage ends, whichever comes first
Job-based coverage from a current employer lets you delay Part B without a penalty. Your Special Enrollment Period starts when the work stops or the coverage ends (COBRA does not extend it, and retiree coverage does not count as current job coverage). Part B then starts the month after Social Security gets your forms. Also: stop paying into a Health Savings Account 6 months before you apply for Social Security or Medicare, to avoid a tax penalty.
If you miss it: the 8 months pass, you wait for the January window (item 3) and the Part B penalty starts counting.
Source: Medicare.gov · Working past 65 · Medicare.gov · When can I sign up for Medicare?
3. Missed your window? The January-to-March catch-up
January 1 to March 31, every year (the General Enrollment Period)
If you missed your first window and have no Special Enrollment Period, this is when you can sign up for Part A and Part B. Coverage starts the month after you sign up.
If you miss it: another full year without Part B, and the penalty grows: an extra 10% of the Part B premium for each full 12 months you could have had Part B but didn't, for as long as you have Part B. Two years late means 20% more every month.
Source: Medicare.gov · When does Medicare coverage start? · Medicare.gov · Avoid late enrollment penalties
4. Drug coverage (Part D): never go 63 days without it
Within 63 days of the end of your first window, or of losing other creditable drug coverage
Even if you take no prescriptions today, you need a Medicare drug plan, a Medicare Advantage plan with drug coverage, or other drug coverage that counts as creditable (your employer or union tells you in a yearly notice, usually in September).
If you miss it: a permanent penalty: 1% of the national base premium ($38.99 in 2026) for every full month you were uncovered, added to your premium for as long as you have Medicare drug coverage, even if you switch plans.
Source: Medicare.gov · Part D late enrollment penalty · Medicare.gov · Avoid late enrollment penalties
5. Medigap: the one-time 6-month window
6 months, starting the first day of the month you are 65 or older AND enrolled in Part B
During these 6 months you can buy any Medigap policy sold in your state, and the company can't turn you down because of your health. If you kept job coverage past 65, the window starts when you sign up for Part B. It happens once.
If you miss it: after the window, your options may be limited and a policy may cost more, except in a few protected situations (item 10). Open Enrollment every fall does not reopen it.
Source: Medicare.gov · When can I buy a Medigap policy? · Medicare.gov · Medigap basics
6. Your plan's Annual Notice of Change
Arrives in September, every year
If you have a Medicare Advantage or drug plan, this letter lists what changes in the plan's coverage and costs on January 1. Read it before Open Enrollment opens on October 15 and check your own drugs and doctors against it.
If you miss it: you find out in January that your drug or your doctor is no longer covered, and the next chance to change is months away.
Source: Medicare.gov · Mailings: costs & coverage
7. Open Enrollment
October 15 to December 7, every year
The one time each year anyone can join, switch or drop a Medicare Advantage plan or a Medicare drug plan, or move between Original Medicare and Medicare Advantage. The plan must get your request by December 7; the change starts January 1. (Medigap is not part of this: see item 5.)
If you miss it: your current plan rolls over for the whole next year as it is, with whatever changed in its notice (item 6).
Source: Medicare.gov · Joining a plan
8. Already in Medicare Advantage and unhappy? The second chance
January 1 to March 31, every year (and your first 3 months on Medicare)
Only if you are already in a Medicare Advantage plan: you can switch to another Medicare Advantage plan, or drop it and go back to Original Medicare and join a separate drug plan. The change starts the first of the month after the plan gets your request.
If you miss it: you stay in the plan until the next Open Enrollment in October, unless a Special Enrollment Period applies to you (moving, losing coverage, getting Medicaid or Extra Help).
Source: Medicare.gov · Joining a plan
9. A life change that opens a Special Enrollment Period
Often 2 full months after the month of the change (moving, losing coverage, getting Medicaid or Extra Help, and other listed events)
Certain events let you join or switch a plan outside the normal windows. After a move, or after other coverage ends, the chance lasts 2 full months after the month it happens; for an exceptional situation that let you sign up for Part A or Part B, you have 2 months to join a plan. Coverage generally starts the first of the month after the plan gets your request.
If you miss it: the short window closes and you wait for the next Open Enrollment.
Source: Medicare.gov · Special Enrollment Periods · Medicare.gov · Joining a plan
10. Protected Medigap rights: 63 days
No more than 63 days after the coverage you are leaving ends
In the situations Medicare lists as guaranteed-issue rights (for example, you joined a Medicare Advantage plan for the first time in the past 12 months and want to go back to Original Medicare) a Medigap company must sell you certain policies regardless of your health, but you must apply within 63 days of the old coverage ending.
If you miss it: the guarantee ends, and the company can ask health questions, charge more or turn you down.
Source: Medicare.gov · When can I buy a Medigap policy?
