When Does Medicare Start? Your Coverage Date, Explained

For most people, Medicare starts on the first day of the month you turn 65, as long as you sign up before that month begins. Sign up later and your start date moves to the first of a following month. If your birthday falls on the first of the month, coverage starts the month before. Below you’ll find the exact rules, a worked calendar, the exceptions that catch people out, and what to do if you live in Bend or elsewhere in Central Oregon.

TL;DR

• Your Initial Enrollment Period is 7 months: the 3 months before your birthday month, the birthday month itself, and the 3 months after.
• Sign up before your birthday month and coverage starts on the first day of that month. Sign up in your birthday month or after, and it starts the first of the next month.
• Still working with employer coverage? You may be able to delay Part B, but the paperwork has to prove continuous coverage.
• Already on a Medigap policy in Oregon? You get a yearly chance to switch plans around your birthday.
• Free, no-pressure help is available locally. We offer it, and so does the state’s SHIBA program.

Table of Contents

• The short answer: the month you turn 65
• How your sign-up month changes your start date
• Do you sign up, or does Medicare find you?
• Part A, Part B and the costs behind the start date
• When you’re still working at 65
• What about Medicare Advantage and the Initial Coverage Election Period?
• Missed your first window? Other start dates
• Medicare doesn’t cover everything: dental, vision and gaps
• Already on Medigap? Oregon’s birthday rule
• Our perspective: the start date is the easy part
• A simple checklist for the 7-month window
• Get a local second pair of eyes
• FAQ
• Sources

The short answer: the month you turn 65

Medicare’s own guidance says coverage generally begins when you turn 65, during a window called the Initial Enrollment Period. That window lasts 7 months. It starts 3 months before the month you turn 65 and ends 3 months after it.

Coverage always starts on the first of a month. If you qualify for premium-free Part A, your Part A starts the month you turn 65. If your birthday is on the first of the month, it starts the month before.

Notice what this means in practice. Medicare doesn’t start on your birthday. It starts on the first day of the month, so you’re covered for the whole month in which you turn 65.

How your sign-up month changes your start date

The rule is simple, but it rewards planning. The same medicare.gov page lays out two cases for Part B:

The consequence is that waiting costs you time. Signing up in your birthday month leaves a gap of nearly a full month with no Medicare. Signing up two months after leaves you uncovered for roughly three months.

A worked example

Say your 65th birthday is on June 18, 2027. Your Initial Enrollment Period runs from March 2027 through September 2027.

• Sign up in March, April or May: coverage starts June 1.
• Sign up in June: coverage starts July 1.
• Sign up in July: coverage starts August 1.
• Sign up in August: coverage starts September 1.
• Sign up in September: coverage starts October 1.

If your birthday is June 1 instead, the first-of-the-month rule shifts everything one month earlier. Your coverage would start May 1, and your window shifts to match.

For most people, the best move is to enroll in the first three months of the window. That way there’s no gap, and you have time to fix any problems before coverage should begin.

Do you sign up, or does Medicare find you?

It depends on whether you already collect Social Security or Railroad Retirement benefits. According to the Oregon SHIBA guide to Medicare plans, the enrollment steps differ for people already receiving those benefits when they turn 65. In general, those people are enrolled in Parts A and B automatically. Everyone else needs to apply.

If you’re not yet taking Social Security, don’t assume anything is happening in the background. Many Bend-area retirees work past 65, and no one will enroll you if you haven’t claimed benefits. Check your status three months before your birthday month.

Part A, Part B and the costs behind the start date

Start dates matter because Medicare isn’t free once it begins. The 2026 premium and deductible figures from CMS show:

• Part B: the standard monthly premium is $202.90, and the annual deductible is $283.
• Part A: most people pay $0 if they or a spouse worked and paid Medicare taxes for at least 40 quarters (10 years). With 30 to 39 quarters, the premium is $311 a month. With fewer than 30 quarters, it is $565 a month.

That is why your start date and your premium start date usually line up. If you enroll in Part B, the premium begins when coverage does. For more detail on what Part A costs here, see our guide to the Part A premium in Central Oregon, or our look at the 2026 Part B premium.

Signing up for Part A later

If you qualify for premium-free Part A, you can sign up any time after you turn 65. Medicare’s guidance says that coverage can reach back 6 months from when you sign up, though not before the month you turned 65. Part B works differently, and it doesn’t reach back in the same way. Don’t treat the two as interchangeable.

When you’re still working at 65

This is where start dates get complicated. Plenty of people keep employer coverage past 65 and delay Part B. Medicare says that if you sign up for 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 your Part B start date up to 3 months.

There’s a bigger risk, though: Medicare warns that signing up later can leave a gap in your coverage and other costs. Delaying is only a good choice when your employer plan counts as creditable coverage for your situation, which depends on factors like your employer’s size.

The paperwork trap

When you delay and later enroll in Part B through a Special Enrollment Period, you must document that you were covered. A Forbes column on Medicare enrollment mistakes describes how the form requesting employment information (CMS-L564) trips people up. The Social Security Administration wants proof of continuous coverage from the date you turned 65 to the present. Having only the last 8 months on paper is often not enough, and incomplete applications can be suspended.

The practical fix: ask your HR department now for a written coverage history, and keep it. Don’t wait until you retire.

What about Medicare Advantage and the Initial Coverage Election Period?

If you want a Part C Medicare Advantage plan instead of Original Medicare with a supplement, there’s a matching window. CMS describes the Initial Coverage Election Period (ICEP) as the timeframe when newly eligible people can enroll in a Medicare Advantage plan. It generally coincides with your first chance to enroll in Parts A and B.

The key point is that the plan choice happens at the same time as the start-date decision. You don’t need to pick everything on day one, but you should know which door you’re walking through. Our overview of Medicare enrollment periods covers the yearly windows, including the fall election period that runs October 15 to December 7, with changes taking effect January 1.

Missed your first window? Other start dates

If you didn’t enroll when first eligible and have no Special Enrollment Period, the General Enrollment Period runs January 1 to March 31 each year. Coverage then begins the month after you enroll. Late enrollment can carry permanent penalties for Part B, so this is a route to avoid if you can.

These are the main routes at a glance:

Medicare doesn’t cover everything: dental, vision and gaps

A start date gives you Parts A and B, not complete coverage. Original Medicare leaves cost-sharing exposure. Part A has its own deductible, which we break down in what Part A covers for Central Oregon residents. Many people also add a Medigap policy, a Part D drug plan or a Medicare Advantage plan.

Routine dental and vision care is the gap many new enrollees find out about after they’ve enrolled. If you want to understand how dental needs change with age, a primary resource on aging and dental health is a useful starting point. When you’re ready to look at coverage options, we help with dental and vision plans alongside your Medicare choices.

Already on Medigap? Oregon’s birthday rule

If you’re past your start date and paying more than you should, Oregon has a consumer protection many states lack. The Oregon Division of Financial Regulation fact sheet says the Medigap Birthday Rule lets you switch to another Medigap plan with equal or lesser benefits once a year. The window starts 30 days before your birthday and ends 30 days after, and you can’t be turned down because of your health.

Three practical points from the same fact sheet:

• Don’t cancel your current policy until the new one is officially issued.
• You may pay two premiums for one month to keep the transition seamless.
• Self-funded employer-sponsored group Medigap plans aren’t eligible.

We’ve written up the details in our guides to the Oregon Birthday Rule 60-day window and how to switch Medigap plans.

Our perspective: the start date is the easy part

As a local agency in Bend, we talk with people approaching 65 every week. The date itself is rarely what trips them up. The harder questions come around it: whether to keep working coverage, which plan type fits their doctors, and what to do about a supplement premium that keeps rising.

We built our practice on education rather than sales. We don’t work from a call-center script, and our consultations are free. We’re paid by the insurance carrier if you choose to enroll through us, and you owe nothing for the conversation if you don’t. Our advice: put your birthday month on the calendar today, count back three months, and treat that as the date to start the process, not the date to finish it.

We also point people to free, non-sales help. Central Oregon residents can get personalized counseling through SHIBA, the state’s Senior Health Insurance Benefits Assistance program, which provides guidance that isn’t tied to selling plans. Use both, compare notes, and decide at your own pace.

— Jesse Zimmerman

A simple checklist for the 7-month window

1. Four months before your birthday month: confirm whether you collect Social Security, and request any employer coverage records if you’re still working.
2. Three months before: your window opens. Enroll now if you want coverage on the first day of your birthday month.
3. Compare plan types: Original Medicare with a supplement and drug plan, or Medicare Advantage. Check that your doctors and prescriptions fit.
4. Birthday month: if you haven’t enrolled, do it now, but expect a start date the following month.
5. Three months after: the window closes. Missing it can mean waiting for the General Enrollment Period and facing penalties.

Our step-by-step guide for turning 65 walks through the same sequence with local detail.

Get a local second pair of eyes

If you’d like someone to check your dates before you commit, our Medicare enrollment assistance is built for exactly this. We explain Parts A, B, C and D, confirm your deadlines and answer questions in person in Bend or remotely. Already enrolled? Our annual Medicare plan reviews check whether your current plan still fits.

FAQ

Does Medicare start on my 65th birthday?

Not exactly. Coverage starts on the first day of a month. If you sign up before your birthday month, it starts on the first day of the month you turn 65. If your birthday is on the first, it starts the month before.

When should I apply for Medicare?

The window opens 3 months before the month you turn 65. Applying in that first stretch gives you coverage with no gap. Applying in your birthday month or later pushes your start to the following month or beyond.

What if I’m still working at 65?

You may be able to delay Part B while you or your spouse have employer coverage, then enroll through a Special Enrollment Period. You’ll need documentation proving continuous coverage, so gather it early. Check with your employer’s benefits office and a Medicare counselor before you delay.

Can I get help with Medicare for free in Bend?

Yes. SHIBA offers free, unbiased counseling for Oregonians. We also offer free educational consultations at Mountaintop Insurance, in person or remotely, with no obligation to enroll.

What is the ICEP?

The Initial Coverage Election Period is the window when newly eligible people can enroll in a Medicare Advantage plan. It generally lines up with your first chance to sign up for Parts A and B.

Sources

• When does Medicare coverage start? (Medicare.gov)
• When can I sign up for Medicare? (Medicare.gov)
• 2026 Medicare Parts A & B Premiums and Deductibles (CMS)
• CY 2026 enrollment and disenrollment guidance (CMS)
• Oregon Medigap Birthday Rule fact sheet (Oregon DFR)
• Oregon Guide to Medicare Insurance Plans (SHIBA)
• Medicare Enrollment Trap: Incomplete Instructions (Forbes)

Recommended

• Medicare Enrollment Periods You Need to Know for 2026
• Medicare Eligibility — When and How You Qualify
• Medicare AEP 2026: Key Dates, Rules, and What’s New
• Medicare Special Enrollment: What Eligible Adults Need to Know

Disclaimer: This article is for general educational purposes only and does not constitute personalized advice. Medicare rules and plan details change frequently.