Medicare enrollment periods: when you can sign up or switch

When you first get Medicare

Initial Enrollment Period

Seven months around your 65th birthday: the 3 months before your birthday month, that month, and the 3 months after. Sign up before your birthday month and Part B starts the month you turn 65. Sign up later in the window and it starts the month after you sign up.

General Enrollment Period

January 1 to March 31, for people who missed their initial window. Coverage starts the month after you sign up. A late penalty may apply.

Job-based coverage

If you (or your spouse) are still working and covered by that job's plan, you may be able to wait. See special enrollment periods below.

Every year

October 15 to December 7: Annual Enrollment Period

Anyone with Medicare can join, switch or drop a Medicare Advantage or Part D drug plan. Changes start January 1.

January 1 to March 31: Medicare Advantage Open Enrollment

Only if you're already in a Medicare Advantage plan. Make one change: to another Medicare Advantage plan, or back to Original Medicare (and join a drug plan). New Medicare Advantage members get a similar one-time change in their first 3 months.

By September 30, your plan sends an Annual Notice of Change listing next year's changes. Read it before December 7.

Medigap open enrollment

Your best time to buy a Medicare Supplement (Medigap) policy is the 6 months starting the first day of the month you're 65 or older and signed up for Part B. It happens once. During it, insurers must sell you any Medigap policy they offer in your state and can't charge more for health problems.

After it ends, insurers in most states can ask health questions and turn you down. A growing number of states give people who already have Medigap a yearly chance to switch. See which states.

Special enrollment periods

Certain events let you change coverage outside the usual dates. Common ones:

Leaving job-based coverage

You can sign up for Part B any time you're covered by a current job's plan, and for 8 months after the job or that coverage ends, whichever comes first. COBRA doesn't extend it.

Moving

Moving out of your plan's service area, or to a place with new plan options, opens a window to switch.

Extra Help or Medicaid

Once a month, you can join a standalone Part D drug plan (with Original Medicare). Since 2025, this monthly change can't be used to join or switch Medicare Advantage plans.

A 5-star plan

Once a year, from December 8 to November 30, you can switch into a plan Medicare rates 5 stars, if one is available where you live.

Losing other coverage

For example, losing Medicaid or leaving a plan that stopped serving your area.

Some special periods need Medicare's approval through 1-800-MEDICARE. A licensed agent or your state's SHIP can tell you which apply to you.

Late penalties

• Part B: 10% added to your monthly premium for each full 12 months you could have had Part B but didn't, usually for as long as you have Part B.
• Part D: 1% of the national base premium, per month, for each full month you went without Part D or other creditable drug coverage after your initial window, or after a gap of 63 days or more. It also lasts as long as you have drug coverage.

There's no Part B penalty if you delayed with job-based coverage and signed up within your special enrollment period, and no Part D penalty if you had other creditable drug coverage or get Extra Help.

Common questions

Keep reading

• What to bring to your first meeting with a Medicare agentA one-page checklist: the cards, doctor list and prescriptions an agent needs to compare plans for you, plus what you should never hand over.
• Medicare Open Enrollment checklist: what to check before December 7A step-by-step checklist for the October 15 to December 7, 2026 Open Enrollment Period: what to read in your plan's letter, what's changing for 2027, what you can switch, and what happens if you do nothing.
• Medicare late enrollment penalties: how they work and how to avoid themHow the Part B, Part D and Part A penalties are figured, with 2026 examples, the situations that let you sign up late without one, and how to challenge a penalty you think is wrong.