Turning 65 in Oklahoma: Your Medicare Checklist

When is my Initial Enrollment Period?

Your Initial Enrollment Period (IEP) is 7 months long: the 3 months before the month you turn 65, your birthday month, and the 3 months after. When your coverage starts depends on when you sign up:

• In the 3 months before your birthday month: coverage starts the first day of your birthday month.
• In your birthday month or the 3 months after: coverage starts the first day of the month after you sign up.

If you miss your IEP and don't have coverage from current work, you may have to wait for the General Enrollment Period (January 1 to March 31) and pay a Part B late penalty of 10% for each full 12 months you could have had Part B, for as long as you have it. See Medicare enrollment periods.

What should I do month by month?

1. 6 months before: gather your information. List your doctors, prescriptions and pharmacy. Ask your employer, union, EGID or retirement system how your coverage works once you have Medicare.
2. 3 months before: sign up. Your IEP opens. Sign up for Part A and Part B with Social Security, unless you're enrolled automatically or are delaying Part B because of job coverage from current work.
3. 2 to 1 months before: choose your coverage. Decide between Original Medicare with a Medigap policy and a Part D plan, or a Medicare Advantage plan sold in your county. Apply so coverage starts with your Medicare.
4. Your birthday month: coverage starts. If you signed up early, Medicare starts the first of the month. Your 6-month Medigap open enrollment period starts when your Part B starts.
5. 3 months after: your IEP ends. This is the last month to sign up without waiting, and your first chance to join a Part D or Medicare Advantage plan ends, unless you have other creditable coverage.
6. 6 months after Part B starts: Medigap window closes. After this, Oklahoma's birthday rule lets you switch Medigap policies each year, but only if you already have one.

What if I already get Social Security?

If you get Social Security or Railroad Retirement Board benefits at least 4 months before you turn 65, you're enrolled in Part A and Part B automatically, and your Medicare card arrives about 3 months before your coverage starts. Part B has a premium ($202.90 a month for most people in 2026), usually taken out of your Social Security payment. If you have job-based coverage from current work and want to delay Part B, follow the instructions that come with the card.

How do I sign up in Oklahoma?

Social Security handles Medicare sign-up for Oklahomans. You can:

• Apply online at ssa.gov/medicare.
• Call Social Security at 1-800-772-1213 (TTY 1-800-325-0778).
• Visit a Social Security office. Find the nearest one with Social Security's office locator.

What if I'm still working at 65?

If you or your spouse are still working and have health coverage from that job, the employer's size decides who pays first. With 20 or more employees, the job-based plan pays first and you can usually delay Part B without a penalty; you get 8 months to sign up after the job or the coverage ends. With fewer than 20, Medicare usually pays first. COBRA and retiree coverage don't count as coverage from current work. See working past 65.

When should I buy Medigap?

Your best chance is your Medigap open enrollment period: the 6 months starting the first month you're 65 and have Part B. During it, any company selling Medigap in Oklahoma must sell you any policy it offers, at the same price as someone in good health (OAC 365:10-5-129(a)). After it ends, Oklahoma's birthday rule gives current Medigap policyholders a 60-day window each year, starting on their birthday, to switch to a policy with the same or fewer benefits without health questions (OAC 365:10-5-129(f)). The birthday rule doesn't apply if you're in Medicare Advantage, so if you might want Medigap, starting with it at 65 keeps your options open. See Medigap in Oklahoma and Medigap vs. Medicare Advantage in Oklahoma.

Do I need Part D now?

If you choose Original Medicare, join a standalone Part D plan during your IEP unless you have other creditable drug coverage, such as from a current employer, VA, TRICARE or IHS. Otherwise you may pay a late enrollment penalty for as long as you have Part D. CMS lists 9 standalone Part D plans in Oklahoma for 2027. Most Medicare Advantage plans include drug coverage. See Part D in Oklahoma.

Can I get help paying costs?

What about HealthChoice, OTRS and other Oklahoma retiree coverage?

• HealthChoice through EGID: EGID's 2027 guide says that to be in a HealthChoice Medicare supplement plan you must be entitled to Part A; Part B isn't required, but the plan pays benefits as if you have it, so you would owe what Part B would have paid. To be in one of EGID's Medicare Advantage options you need both Part A and Part B. Call EGID Member Services at 405-717-8780 or 800-752-9475 before your Medicare starts.
• Teachers (OTRS) and other public retirees: ask OTRS, your former employer and EGID how your retiree health coverage works once you're eligible for Medicare.
• City, county, university and private employer retirees have their own rules. Ask your benefits office what it requires.

See state and teacher retirees and Medicare.

Tribal citizens and IHS

The Indian Health Service's Oklahoma City Area says Oklahoma is home to more than 39 tribes and tribal organizations, and many tribes run their own health systems. Signing up for Medicare doesn't replace IHS or tribal health care; it adds coverage for care outside those facilities, and IHS and tribal facilities can bill Medicare for care they give you. CMS says drug coverage through IHS, tribal and urban Indian health programs counts as creditable coverage for Part D, so you won't owe a Part D late penalty for that time. IHS isn't health coverage from a current job, so it doesn't let you delay Part B without a penalty. Ask your tribal health system's benefits coordinator for help. See tribal health and Medicare in Oklahoma.

Veterans and military retirees

VA health care and Medicare generally don't pay for the same service: the VA pays for care at VA facilities, such as those of the Oklahoma City VA Health Care System and the Eastern Oklahoma VA Health Care System, and Medicare pays for Medicare-covered care elsewhere. Many veterans keep Part B so they can also see providers outside the VA. If you have TRICARE, you generally need Part A and Part B to keep TRICARE For Life once you're eligible for Medicare. See veterans, TRICARE and military retirees.

Your turning-65 checklist

1. Mark your IEP dates. Put the first and last months on your calendar.
2. Sign up for Part A and Part B. Apply with Social Security, or confirm you're enrolled automatically.
3. Check your other coverage. Call your employer, EGID, OTRS, the VA or TRICARE, and your tribal health system if you use one.
4. Choose your coverage. Original Medicare with Medigap and Part D, or Medicare Advantage.
5. Check for help paying. See if you qualify for SoonerCare Supplemental or Extra Help.
6. Keep your papers together. Your Medicare card, letters and creditable coverage notices.

When you're ready to look at coverage, see plans for your ZIP code, or you can request a call from a licensed insurance agent to go over plans from the companies they work with, at no cost to you. See also Medicare eligibility and Medicare basics.

Sources

• Medicare.gov — When does Medicare coverage start?
• Medicare.gov — How do I sign up for Medicare?
• Social Security — Sign up for Medicare
• Social Security — Office locator
• Medicare.gov — Avoid late enrollment penalties
• Okla. Admin. Code § 365:10-5-129, Medigap open enrollment and birthday rule (via Cornell LII)
• Oklahoma Insurance Department — New Medicare Supplement Open Enrollment FAQs
• OMES Employees Group Insurance Division — 2027 Medicare Options Benefit Guide (Part A and Part B requirements)
• Oklahoma Health Care Authority — SoonerCare Supplemental (QMB, SLMB, QI-1)
• Oklahoma Human Services — SoonerCare
• Indian Health Service — Oklahoma City Area
• Indian Health Service — Dear Tribal Leader and Urban Indian Organization Leader letter, October 15, 2026 (Part D creditable coverage)
• TRICARE — TRICARE For Life

Frequently asked questions

Medicare in your Oklahoma county

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