Your seven-month window
| When you sign up | When Part B starts |
|---|---|
| 1 to 3 months before your birthday month | The first day of your birthday month |
| In your birthday month | The first day of the next month |
| 1 to 3 months after your birthday month | The first day of the month after you sign up |
| After your window closes | General Enrollment Period (Jan 1 to Mar 31); coverage starts the month after you sign up, and a penalty may apply |
If you already get Social Security benefits, you don't need to do anything: you're enrolled automatically and your card comes about three months before your birthday month. For how to apply, see how do I sign up for Medicare in Oklahoma.
A turning-65 checklist
- Three months before your birthday month. Apply at ssa.gov or call Social Security at 1-800-772-1213, unless you're enrolled automatically.
- Decide on drug coverage. Choose a Part D plan or a Medicare Advantage plan with drug coverage in the same window, unless you have other creditable coverage.
- Look at Medigap. If you'll keep Original Medicare, your six-month Medigap open enrollment starts with Part B. After that, Oklahoma's birthday rule lets you switch to equal or lesser benefits each year for 60 days from your birthday.
- Check help with costs. If your income is limited, apply for a Medicare Savings Program at your OKDHS Human Services Center.
- Check your other coverage. Retirees with HealthChoice (EGID, part of OHCA) or OTRS coverage, TRICARE For Life, or IHS and tribal health care should check how each works with Medicare.
Oklahoma choices once you're enrolled
CMS data show 50 Medicare Advantage plans open to everyone and 9 standalone Part D plans in Oklahoma for 2027, and Medicare Advantage choices differ by county. Seven western and Panhandle counties have only special needs plans for 2027. See turning 65 in Oklahoma and Medigap in Oklahoma.
Get help
A licensed insurance agent who works with Benefits Life can walk you through your choices at 65 and compare plans from the companies they work with, at no cost to you. You can request a call from a licensed insurance agent, or see plans for your ZIP code. See also Medicare enrollment periods.
Related questions
Do I need Part B if I'm still working?
When you can wait.
What are the 2027 deadlines?
The full calendar.
How much does Medicare cost per month?
Premiums you can expect.
Sources
- Medicare.gov — When does Medicare coverage start?
- Medicare.gov — Avoid late enrollment penalties
- Medicare.gov — When can I buy Medigap?
- Oklahoma Insurance Department — Medicare Supplement Open Enrollment FAQs
- CMS — CY2027 Medicare Advantage and Part D Landscape files
More questions in this guide
- Do I need Medicare Part B if I'm still working at 65?
- How do I sign up for Medicare in Oklahoma?
- What are the Medicare deadlines in Oklahoma for 2027?
- What happens to my Medicare plan if I move to Oklahoma?
Part of the guide: Medicare enrollment periods in Oklahoma · All questions
Frequently asked questions
My birthday is on the 1st. Does that change anything?
Yes. Medicare treats you as turning 65 the month before, so your whole seven-month window and your coverage start date move one month earlier.
Do I need to join a Part D plan at 65 too?
If you don't have other creditable drug coverage, join a Part D or Medicare Advantage drug plan during the same seven-month window. Waiting can mean a Part D late penalty for as long as you have drug coverage: 1% of the national base premium ($38.99 in 2026) for each full month you went without.
When should I buy a Medigap policy?
Your six-month Medigap open enrollment period starts the month your Part B begins and you're 65 or older. During it, companies can't turn you down or charge more because of your health.
What if I'm still working at 65?
If you have group coverage from current work at an employer with 20 or more employees, you can delay Part B without a penalty and sign up within eight months after that job or coverage ends.
Medicare in your Oklahoma county
Plans, local agents and help, county by county: Oklahoma · Tulsa · Cleveland · Canadian · Comanche · Rogers · Wagoner · Payne · Pottawatomie · Creek · Muskogee · Garfield · Grady · Washington · Logan · Bryan · Le Flore · Carter · Cherokee · McClain · All 77 counties →
