Medicare Supplement

Turning 65 in Tustin? Your Six-Month Medigap Window Starts Now

TUSTIN, Calif. — If you are approaching 65 in Tustin, there is one Medicare deadline that quietly matters more than almost any other. It is not the fall Annual Enrollment Period, and it is not tied to Medicare Advantage. It is the six-month Medigap Open Enrollment Period, and it opens the month you turn 65 and are enrolled in Medicare Part B. Miss it, and the rules for buying a Medicare Supplement policy can change in ways that surprise people.

Here is what every soon-to-be-65 reader in Orange County should know before that clock runs out.

What the Medigap Open Enrollment Period actually is

Medigap — also called Medicare Supplement Insurance — is a private policy that helps pay some of the out-of-pocket costs Original Medicare (Parts A and B) leaves behind, such as coinsurance and copays.

Federal law gives you one guaranteed six-month window to buy any Medigap policy sold in your state. That window begins the first month you are both 65 or older and enrolled in Medicare Part B. It runs for six months straight and does not restart.

According to CMS guidance on Medicare Supplement Insurance (medicare.gov), during this period an insurer cannot:

• Refuse to sell you any Medigap policy it offers,
• Make you wait for coverage to start (with limited exceptions for pre-existing conditions), or
• Charge you a higher premium because of your health history.

That combination of protections is not available at any other guaranteed time for most people.

Why this window matters more than most Medicare dates

Tustin is in Orange County, where residents have a wide range of Medicare choices each year — including many Medicare Advantage and Part D plans that can be reviewed during the Annual Enrollment Period (October 15 – December 7) or the Medicare Advantage Open Enrollment Period (January 1 – March 31).

Those windows let you switch Medicare Advantage or Part D plans. They do not give you the same guaranteed right to buy a Medigap policy. That is what makes the six-month Medigap window unique: it is the one time federal law forces insurers to say yes.

What changes after the six months end

Once your Medigap Open Enrollment Period closes, most states (California included) allow insurers to use medical underwriting when you apply for a new Medigap policy. That means the insurer can:

• Ask health questions,
• Charge a higher premium based on your health, or
• Decline to sell you a policy at all.

There are a few limited "guaranteed issue" situations later on — for example, if certain kinds of coverage end through no fault of your own. California also has a yearly "birthday rule" that lets Medigap enrollees switch to certain policies around their birthday. But these are narrower than the one-time six-month window, and the rules can be tricky.

For a rundown of guaranteed-issue rights and state-specific protections, medicare.gov is the official source.

Common mistakes to avoid

A few missteps come up again and again for people turning 65:

• Delaying Part B without a good reason. Your Medigap window does not open until you are enrolled in Part B. Waiting can push your guaranteed six months into a less convenient time.
• Assuming you can "try" Medicare Advantage and switch to Medigap later with no health questions. In most cases, once your six months pass, insurers can underwrite. There is a limited "trial right" in some situations, but do not count on it without checking the specifics.
• Confusing Medigap with Medicare Advantage. They are different products. You generally cannot use a Medigap policy to pay costs under a Medicare Advantage plan, and you cannot have both at once.
• Shopping on price alone. All Medigap plans of the same letter (Plan G, Plan N, etc.) offer the same standardized benefits, but premiums and customer service vary by insurer.

How to use your window wisely

If you are approaching 65 in Tustin, a simple plan of action helps:

1. Confirm your Part A and Part B start date at medicare.gov or by calling 1-800-MEDICARE (1-800-633-4227). 2. Mark the six-month Medigap window on your calendar the moment Part B begins. 3. Compare Medigap plan letters (they are standardized) and the insurers that offer them in California. 4. Decide whether Medigap plus a standalone Part D plan, or a Medicare Advantage plan, better fits how you use care. 5. Get free, unbiased help from your State Health Insurance Assistance Program (SHIP). In California, that program is called HICAP and serves Orange County residents at no cost.

A note on 2026 program figures

While you are weighing your options, a few program-level facts for 2026 are worth knowing, because they affect the drug coverage side of the picture:

• The Part D out-of-pocket cap is $2,100 in 2026.
• The Part D maximum deductible is $615.
• The old coverage gap (the "donut hole") has been eliminated; Part D now has three phases.
• The optional Medicare Prescription Payment Plan lets you spread drug costs across the calendar year in monthly amounts.
• IRMAA surcharges on Part B and Part D premiums begin above $109,000 in income for a single filer in 2026.

These figures do not change the Medigap window itself, but they shape the total cost of your Medicare coverage.