Medicare Enrollment Periods

Your first chance to sign up for Medicare lasts seven months: the three months before the month you turn 65, your birthday month, and the three months after. The same seven months are your first window to join a drug plan or a Medicare Advantage plan.

If you already collect Social Security or Railroad Retirement benefits at least four months before 65, you don’t need to act. You are enrolled in Parts A and B automatically, and your card arrives about three months before coverage starts. Everyone else applies through Social Security.

Premium-free Part A starts the month you turn 65, or the month before if your birthday falls on the first of a month. When Part B starts depends on when you sign up:

If you or your spouse are still working and covered by that employer’s group health plan, you can usually delay Part B without a penalty. When the job or the coverage ends, whichever comes first, an 8-month Special Enrollment Period opens. It starts then even if you elect COBRA, and COBRA doesn’t extend it. Retiree coverage, Marketplace plans and other individual insurance never open this window, so people relying on them should sign up during their Initial Enrollment Period.

For drug coverage, you get two full months after the month your employer coverage ends to join a Part D or Medicare Advantage plan, with no penalty if that coverage was creditable. A few timing moves avoid gaps and tax problems:

Miss your Initial Enrollment Period without qualifying job coverage and your fallback is the General Enrollment Period, January 1 to March 31 each year. Coverage starts the month after you sign up. You may also owe the Part B late penalty: 10% of the standard premium for each full 12-month period you could have had Part B but didn’t, generally for as long as you have Part B. If you have to buy Part A, a late start adds 10% to its premium for twice the number of years you waited.

Medicare also grants exceptional-circumstance Special Enrollment Periods, most lasting six months or more, for situations that arose on or after January 1, 2023. You request them through Social Security, and Part B taken up this way carries no late penalty.

Once you have Medicare, other windows govern how you get it. Open Enrollment runs October 15 to December 7, with changes effective January 1. During it you can switch between Original Medicare and Medicare Advantage, change Advantage plans, and join, switch or drop a Part D drug plan.

From January 1 to March 31, the Medicare Advantage Open Enrollment Period gives people already in an Advantage plan one switch: to another Advantage plan, or back to Original Medicare with the option of a drug plan. New enrollees who chose Advantage get the same one-time switch in their first three months with Parts A and B.

Special Enrollment Periods for plans follow life events, each on its own clock. A move out of your plan’s service area gives you two full months after the move, starting a month earlier if you tell the plan in advance. People with Medicaid or Extra Help can change drug plans once a month, and the five-star Special Enrollment Period lets you switch once between December 8 and November 30 into a plan rated five stars where one is offered.

Medigap has a one-time window of its own. Medigap Open Enrollment lasts six months, starting the first day of the month you are both 65 or older and enrolled in Part B. During it, insurers can’t refuse to sell you a policy or charge more because of your health. Afterward there is no federal guarantee, although some states give extra rights.

That makes the timing of Part B the timing of Medigap. Delay Part B while on an employer plan and the Medigap window waits until Part B starts. Join Medicare Advantage at 65 and later want Original Medicare with a supplement, and you may pay more or be turned down. The main exception is a trial right: if you joined Advantage when first eligible at 65 and leave within the first 12 months, you return to Original Medicare with special rights to buy a Medigap policy.