Blog / Medigap

How do I enroll in a Medicare Supplement?

You apply straight with the insurance company, not with Medicare. Your timing decides whether they can ask health questions and turn you down.

Updated September 3, 2026 · 3 min read · by Gerino Alejos

A Medicare Supplement is bought with an insurance application, not a Medicare enrollment. You apply straight with the insurance company. Medicare is not part of it beyond your Part A and Part B enrollment.

What you need first

• Enrollment in both Part A, the hospital part, and Part B, the part that pays for doctor visits.
• Your Medicare number and the start dates for Part A and Part B, printed on your red, white and blue card.
• Ideally, to be inside your six month Medigap open enrollment window.

That last item is not a requirement, but it changes everything about the application. See your open enrollment window.

The timing that decides the outcome: your six month window

The window runs six months and starts when your Part B begins, at or after 65. Inside it, no Texas company can turn you down or charge more for your health history. The application is close to a formality.

Outside the window, the company can use underwriting, which means it looks at your health history and can say no. You answer health questions, and you may be charged more or turned down. The exception is a guaranteed issue right, a window when a company must take you.

Choosing before you apply

1. Pick your plan letter. Plan G suits most people new to Medicare. Plan N has a lower monthly bill and small copays, a set amount you pay at a visit. High deductible Plan G costs much less each month, after a deductible you pay yourself first. See choosing a letter.
2. Get quotes for that letter from several companies.
3. Ask each one how it sets rates, and how much it has raised them before.
4. Ask about household and payment discounts.
5. Choose on price, since coverage under a letter is the same by law. See comparing rates.

The application

• Your personal details and your Medicare information.
• Health questions, if you are outside a protected window.
• The date you want the coverage to start.
• Payment setup, often with a discount for paying from your bank account.

Answer the health questions accurately. A wrong answer can let the company rescind the policy later, cancelling it after the fact. That is worse than being turned down today.

The order that avoids a gap

1. Apply, then wait for written approval with a confirmed start date.
2. Sign up for a standalone Part D plan, a separate drug plan, for that same start date, because a supplement pays nothing toward prescriptions. See why you need Part D.
3. If you are leaving a Medicare Advantage plan, drop it only after the supplement is approved. See switching from Advantage.
4. If you are replacing a supplement you already have, set the old one to end the day before the new one starts.
5. Get everything in writing before any coverage ends.

After you are approved

You get a policy and a card. Carry it with your Medicare card. Your doctor bills Medicare, which sends the balance to the company on its own, so you should not have to file claims.

You also get a 30 day free look period. Cancel inside those 30 days and you get your money back.

There is nothing to renew each year. A Medigap policy is guaranteed renewable, so the company must keep it going as long as you pay the monthly bill. Checking your rate against the market every couple of years is still worth doing, while your health would let you move.

Your next step is to check the start date on your Part B, then get quotes for one plan letter. Call our McAllen office at (956) 687 3334, or enter your ZIP code in the plan pricing box on this page.

Gerino Alejos

Licensed insurance agent · License 3128710 · NPN 18243381

Owner of McAllen Insurance Group, an independent agency on North 10th Street in McAllen. Works with clients across Hidalgo, Cameron and Starr counties on Medicare, Marketplace health, life and auto coverage. Se habla español.