Missed your Medicare enrollment window in Wyoming: what happens next

By Heather Huhn, Licensed Independent Insurance Agent (NPN 19222086) · Updated September 6, 2026 · Jackson Hole, Wyoming

Short version: if your seven-month window around 65 closed without you signing up for Part B, you still have two doors. The General Enrollment Period runs January 1 through March 31 every year and is open to everyone. A Special Enrollment Period is open to people in certain situations, most often those who kept working past 65, and it carries no late penalty. Here is which door fits, when coverage starts, and what the penalty is if one applies.

What was my Initial Enrollment Period?

Your Initial Enrollment Period runs seven months: the three months before the month you turn 65, that month, and the three months after. It is the one window that carries no late penalty. If it closed without you signing up for Part B, you now sign up in one of the windows below.

Premium-free Part A is the exception, and it is good news. You can sign up for it any time after 65, and coverage can be backdated up to six months, though never earlier than the month you turned 65. So a missed window usually means Part B and drug coverage are the pieces to place, not hospital coverage.

When can I sign up now?

The General Enrollment Period runs January 1 through March 31 every year. Sign up in it and your Part B coverage starts the first day of the month after you sign up. That is a change from the old July 1 start date, and it means less time between the paperwork and the coverage.

The arithmetic is simple: sign up in January and you are covered February 1, sign up in February and you are covered March 1, sign up in March and you are covered April 1. Signing up early in the window is worth doing. Social Security takes the Part A and Part B application, online or at a local office.

Do I qualify for a Special Enrollment Period?

A Special Enrollment Period lets you sign up outside the General Enrollment Period and skips the late penalty. The most common one covers people who had health coverage through a job. Others cover a lost Medicaid case, a declared disaster, incorrect information from a plan or employer, and release from incarceration.

The exceptional-condition periods above were added by CMS for situations starting on or after January 1, 2023, and each one is claimed on form CMS-10797, sent to Social Security. They generally run six months, and coverage generally begins the month after you sign up. This is the first thing worth checking, because it is the door with no penalty attached.

What if I worked past 65?

If you or your spouse had group health coverage from current work, your Special Enrollment Period starts the month after your Initial Enrollment Period ends. It runs for eight months after the job ends or the group coverage ends, whichever comes first. Sign up inside it and there is no Part B penalty.

There is also a timing lever inside this window. If you enroll in Part B while you or your spouse are still working, or within the first full month after employer coverage ends, you can ask to delay the Part B start date by up to three months. That lets a group plan and Part B line up cleanly instead of overlapping.

Does COBRA or retiree coverage extend my window?

COBRA and retiree coverage are not counted as group health plan coverage from current work, so they do not extend the eight-month Special Enrollment Period. That clock is set by the job ending or the group plan ending. Knowing this early is what keeps a Part B start date on schedule.

The same is true of a Marketplace plan bought on HealthCare.gov. It is real coverage and it does its job, and it also runs on its own track rather than extending a Medicare window. When someone is on COBRA, retiree coverage or a Marketplace plan and turning 65 is behind them, the eight-month clock is the number to find first.

What is the Part B late enrollment penalty?

Part B adds 10% for each full 12-month period you could have had Part B and did not. It is added to the monthly premium and stays for as long as you hold Part B. A Special Enrollment Period or a Medicare Savings Program generally clears it.

Two things follow from that. The penalty is measured in whole 12-month periods, so eleven late months and one late month land in the same place. And because it rides on the premium rather than arriving as a one-time bill, the number worth knowing is the percentage, which is fixed once your enrollment date is set.

What about the Part A and Part D penalties?

Most people get premium-free Part A and never see a Part A penalty. If you have to buy Part A, the penalty is 10% and you pay it for twice the number of years you waited. Part D adds 1% a month, or 12% a year, and it stays as long as you hold drug coverage.

Can I still get a drug plan?

Yes. Once your Part A or Part B is in place you can join a Medicare drug plan. The Part D penalty applies only if you went 63 days or more without creditable drug coverage, which is coverage at least as good as Part D. Creditable coverage from a job protects you.

Timing runs off your enrollment. If you sign up for Part A or Part B during a Special Enrollment Period for an exceptional situation, you have two months to join a drug plan or a Medicare Advantage plan. Otherwise the fall Open Enrollment Period, October 15 through December 7, is the next door, with coverage starting January 1.

What happens to Medigap when Part B starts later?

Your Medigap Open Enrollment Period is six months and it starts the first month you have Part B and are 65 or older. Inside it an insurer must sell you any Medigap policy it offers and cannot use your health history. It happens once, so the Part B start date is worth planning.

That is the reason a late Part B enrollment is worth treating as one decision rather than two. The date you choose sets the drug-plan clock and the Medigap clock at the same time. Outside that six-month window, medical underwriting can apply, and separate guaranteed issue rights cover a shorter list of situations.

What should I do this week?

Six steps, in order. Most of the work is finding two dates and one letter — the day your group coverage ended, the Part B start date you want, and your last creditable coverage notice. With those three in hand, the rest of the enrollment is paperwork.

• Find the date your job or your group coverage ended. That single date decides whether the eight-month Special Enrollment Period is still open.
• Check the exceptional-condition list. A lost Medicaid case, a declared disaster, or incorrect information from a plan or employer each opens a six-month window on form CMS-10797.
• If no Special Enrollment Period fits, put January 1 in the calendar and file early in the window so coverage starts February 1.
• Pull your last creditable coverage letter. It is what settles the 63-day question for Part D.
• Decide the Part B start date before you file, because it starts the Medigap six-month window too.
• Write down which doctors and prescriptions have to keep working. That is what picks the plan once the enrollment date is set.

We do this work for people across Teton County and the rest of Wyoming, and we are licensed in Wyoming, Idaho, Montana, Colorado, California and Texas. If you are still sorting out the timeline itself, read turning 65 in Jackson Hole: the Medicare timeline, in order. For the plan side of it once your dates are set, read next on our Medicare page, pick a time, or call 307-284-3060.

Questions people ask

Can I sign up for Medicare after 65 if I missed my Initial Enrollment Period?

Yes. The General Enrollment Period runs January 1 through March 31 every year and is open to anyone who missed an earlier window. Coverage starts the first day of the month after you sign up. If a Special Enrollment Period applies to you, use that one instead and the late penalty does not apply.

When does coverage start if I sign up during the General Enrollment Period?

The month after you sign up. Sign up in January and coverage starts February 1; sign up in March and coverage starts April 1. This has been the rule since the 2023 effective-date change, which replaced the old July 1 start and shortened the gap between signing up and being covered.

How long does the Part B late enrollment penalty last?

For as long as you hold Part B. The amount is an extra 10% of the monthly premium for each full 12-month period you could have had Part B and did not. It is not a one-time fee. A Special Enrollment Period or a Medicare Savings Program generally clears it.

Does COBRA count as employer coverage for Medicare?

No. Medicare counts group health plan coverage from current work, and COBRA is not current work, so it does not extend the eight-month Special Enrollment Period. That eight-month clock starts when the job ends or the group plan ends, whichever comes first, and COBRA runs alongside it rather than pausing it.

Sources

• Medicare.gov — When does Medicare coverage start?
• Medicare.gov — Avoid late enrollment penalties
• Medicare.gov — Joining a plan: enrollment periods
• Medicare.gov — Medigap: get ready to buy
• CMS — Form CMS-10797, Special Enrollment Period for exceptional conditions
• CMS — CMS-4199-F fact sheet, 2023 enrollment effective-date change
• SSA — Sign up for Medicare
• CMS — Wyoming State Health Insurance Information Program (WSHIIP) contact

All dates, percentages and rules on this page were read September 6, 2026 from the sources above. This page is general information, not legal or tax advice. Not affiliated with Medicare or any government agency. We do not offer every plan available in your area. Please contact Medicare.gov or 1-800-MEDICARE to get information on all of your options.