Medicare Supplement

Before Part B starts in Laguna Niguel? Read this Medigap rule

LAGUNA NIGUEL, Calif. — If you are approaching 65 in Laguna Niguel, there is one Medicare rule that quietly shapes the rest of your coverage life: the six-month Medigap Open Enrollment Period. It starts the month you are 65 and enrolled in Medicare Part B, and it is the single window when a Medigap insurer must sell you any policy it offers at its best available rate — no health questions, no denials, no surcharges for pre-existing conditions.

Miss it, and the rules change for good.

What Medigap 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, like coinsurance and hospital costs. Medigap works alongside Original Medicare. It is not the same as a Medicare Advantage plan, and you generally cannot have both at the same time.

Medigap policies are standardized by letter (Plan G, Plan N, and so on). The same lettered plan offers the same core benefits from one carrier to another; the price and customer service are what differ.

Why the six-month window matters so much

Federal law gives every new enrollee one guaranteed shot at Medigap. According to CMS, your Medigap Open Enrollment Period is a six-month stretch that starts the first month you have Medicare Part B and are 65 or older. During those six months:

• Any insurer selling Medigap in your area must sell you a policy they offer.
• They cannot charge you more because of a health condition.
• They cannot make you wait for coverage of pre-existing conditions if you had at least six months of prior "creditable" coverage.

This is the only time these three protections are guaranteed nationwide. It is why so many Medicare counselors urge people to at least consider Medigap before this window closes, even if they choose something else.

What changes when the window closes

Once your six months are up, most states — including California — allow Medigap insurers to use medical underwriting if you try to enroll or switch later. That means the carrier can:

• Ask health questions.
• Charge you a higher premium based on your health history.
• Deny your application altogether.

California does offer some added protections, including a "birthday rule" that lets existing Medigap policyholders switch to certain equal-or-lesser plans each year around their birthday without underwriting. But the birthday rule is for people already in a Medigap plan — it does not replace the one-time guaranteed enrollment window.

There are also limited "guaranteed issue" situations later on — for example, if an employer plan ends or a Medicare Advantage plan leaves your area — but those are narrower than the initial six-month window.

How this fits with your other Medicare choices in Orange County

Laguna Niguel is in Orange County, where residents can choose between Original Medicare (often paired with a Medigap policy and a stand-alone Part D drug plan) or a Medicare Advantage plan that bundles coverage. Orange County has a wide selection of Medicare Advantage and Part D plans available through multiple carriers, and specific plan details change every year during the Annual Enrollment Period (Oct. 15 – Dec. 7).

The important point for the Medigap window: the choice you make in your first months on Medicare has long-term consequences. If you pick Medicare Advantage now and later want to switch to Original Medicare with a Medigap policy, you may face underwriting — unless a specific guaranteed-issue right applies.

A few 2026 numbers worth knowing

Even if your focus is Medigap, these program-level figures for 2026 help frame the bigger picture:

• Part D out-of-pocket cap: $2,100.
• Part D maximum deductible: $615.
• The old coverage gap ("donut hole") remains eliminated; Part D has three phases.
• IRMAA income surcharges begin above $109,000 for single filers.
• The Medicare Prescription Payment Plan lets you spread drug costs across the year.

Practical steps before your window closes

• Mark the exact start and end date of your six-month Medigap Open Enrollment Period on your calendar.
• Compare the standardized Medigap plan letters at medicare.gov so you understand the benefit differences before shopping on price.
• If you are still working past 65 and delaying Part B, remember your Medigap window will not start until Part B does.
• Talk to California's free SHIP program — known locally as HICAP — before making a final decision.