Month by month around 65

The seven months around the month you first became eligible

If you already have Medicare, this first window is behind you. A fall change uses Annual Enrollment.

When you first could join a Medicare Advantage plan

If you already have Medicare, a later Advantage change uses Annual Enrollment, Medicare Advantage Open Enrollment, or a Special Enrollment Period.

January 1 – March 31, 2026

If you missed Initial Enrollment and you do not have a Special Enrollment Period, you can sign up for Part A and Part B during these dates. Coverage usually starts the month after you enroll, and a late penalty can apply. These months are also Medicare Advantage Open Enrollment, which is a different window.

January 1 – March 31, 2027

This window is not open on this date. It runs January 1 through March 31, 2027, and only for someone who is in a Medicare Advantage plan. It is not open during Annual Enrollment.

Six months from the month Part B starts, if you are 65 or older

Enter a Part B start date to see the dates. This is not Annual Enrollment and not the California Birthday Rule. Under 65, the rule is different.

60 days starting on your birthday

This window is only if you already have a Medicare Supplement in California. It is not a way to leave a Medicare Advantage plan.

While the job coverage lasts, and typically 8 months after the job or the coverage ends, whichever is first

Coverage from a current employer of 20 or more people, including a working spouse, may let you delay Part B. COBRA usually does not extend this window. Part D uses a shorter clock, often two months. Get the proof in writing. This is not a determination.

Often the month before the move through two months after it

A move out of your plan’s service area can let you pick a new Medicare Advantage or Part D plan. The exact months depend on when you tell the plan. Confirm the dates for your move.

Once a month, if you have Extra Help or Medicaid

People with Extra Help, Medi-Cal, or a Medicare Savings Program may switch to Original Medicare and a stand-alone Part D plan, or switch stand-alone Part D plans, once a month. This does not let you join a new Medicare Advantage plan. Some people with full Medi-Cal can also join certain integrated Dual Special Needs Plans once a month. A government agency decides whether you qualify. This form does not.

The dates in the letter from Medicare or the plan

If your Medicare Advantage or Part D plan is leaving Medicare or leaving your area, the notice gives the window. Do not guess those dates from this form.

During the first 12 months in a Medicare Advantage plan, in the situations Medicare allows

In some first-year cases you can drop Medicare Advantage and return to Original Medicare, and you may have a right to buy a Supplement without health questions. There is more than one trial right. Confirm which one fits before you drop a plan.

While you live in a qualifying institution, and for up to two months after you leave

A move into or out of a nursing home or similar institution can open a window to join or change a plan. The facility has to qualify. Confirm that on Medicare.gov.