The short answer
Signing up for Medicare and changing a Medicare plan are different tasks. Start with your current coverage and the change you need to make.
Which kind of enrollment do you mean?
First Medicare enrollment
Usually the seven-month window around turning 65. Some people qualify earlier or have a special enrollment opportunity.
Fall plan changes
Oct 15–Dec 7Join, switch or drop Medicare Advantage or drug coverage. Changes generally start January 1.
Medicare Advantage changes
Jan 1–Mar 31If already in Medicare Advantage, make one change to another Advantage plan or return to Original Medicare and join a drug plan.
A qualifying life change
A move or coverage change may open a Special Enrollment Period. The event, coverage type and deadline determine your options.
Missed your initial Part A/Part B enrollment? A General Enrollment Period runs January 1–March 31. It is different from the Medicare Advantage window. Check whether a Special Enrollment Period applies first.
Turning 65 is its own milestone
The usual Initial Enrollment Period lasts seven months: three before your birthday month, that month, and three after. A birthday on the first of a month changes the timing. Confirm your dates and whether you will be enrolled automatically.
Still working or losing coverage?
An employer coverage Special Enrollment Period may apply to Part B. COBRA and retiree coverage are not the same as coverage based on current employment. Do not wait for an annual plan-change window to check your Part B deadline.
Medigap follows separate rules
Your federal Medigap Open Enrollment Period generally lasts six months starting when you are both 65 or older and enrolled in Part B. Fall Medicare Open Enrollment does not create a general right to buy any Medigap policy. State protections may differ.
Avoid preventable penalties
Delaying Part B without a qualifying exception can lead to a lasting penalty. Part D can also have a penalty after 63 consecutive days without Part D or other creditable drug coverage following your initial enrollment period. Verify medical and drug coverage separately.
A question worth asking
Can a move or loss of coverage let me change plans?
Sometimes. Special Enrollment Periods have specific qualifying events and deadlines. A life change alone does not guarantee every type of enrollment opportunity.
Your next-step checklist
Use this for your own notes. Checkmarks are not sent to Finwell or saved when you leave.
Sources & review
Checked against the official sources below on September 11, 2026. General education, not an individual coverage or eligibility determination.
When to sign up — Medicare.govJoining a plan — Medicare.govMedigap enrollment — Medicare.govLate enrollment penalties — Medicare.govCoverage and enrollment rules can change. Confirm the details for your situation with Medicare, Social Security, your state or the specific plan. Tell us if something needs clarification.
Keep learning
Working past 65 or getting ready to retire?
Coordinate employer coverage, Medicare and your retirement dates.
Read the next guide →