Medicare Supplement

Medigap in Seattle for 2026: the rules, the reset, and how to check rates

SEATTLE — If you have a Medigap policy, or you're thinking about buying one, a few things are worth knowing before the new year. Medigap works differently from Medicare Advantage: the plans are standardized by letter, most changes happen quietly through state rate filings, and the calendar — not a fall enrollment window — often decides what you can buy and what you'll pay. Here's what Seattle readers should have on their radar for 2026.

Which plan letters you can actually buy

Seattle is in King County, and Medigap availability in Washington follows federal standardization rules. If you're newly eligible for Medicare today, these are the standardized letters open to you: A, B, D, G, G-HD (the high-deductible version of G), K, L, M, and N.

Plans C and F are still sold, but only to people who were eligible for Medicare before January 1, 2020. That rule hasn't changed, and it isn't changing in 2026. If you turned 65 recently, or you're about to, C and F simply aren't options — no matter which insurer you call.

The January reset that affects Plans G and N

Plans G and N are the two most commonly purchased letters for new enrollees, and both are designed around the Part B deductible. You pay that deductible out of pocket each year before Medigap picks up its share of Part B costs.

That deductible resets every January 1. The 2026 amount is published by CMS on medicare.gov — check it there rather than relying on last year's number. The high-deductible version of Plan G (G-HD) works on a much larger annual deductible that is also reset by CMS each year.

Nothing about the structure of G or N is changing for 2026. What changes is the dollar figure behind them, which is why it's worth a quick look before you renew or shop.

Washington doesn't do "open enrollment" for Medigap

This is where a lot of Seattle readers get tripped up. The October 15–December 7 Annual Enrollment Period and the January 1–March 31 Medicare Advantage Open Enrollment Period are for Part D and Medicare Advantage. They are not Medigap windows.

Your strongest Medigap protections are:

• Your 6-month Medigap Open Enrollment Period, which starts the month your Part B begins. During that window, insurers must sell you any Medigap policy they offer at their best available rate, regardless of health history.
• Guaranteed-issue rights, which can be triggered by specific events — for example, if your Medicare Advantage plan leaves the area, or your employer coverage ends.

Outside those windows, in Washington, insurers can generally use medical underwriting when you apply, which may affect whether you're offered a policy and at what price. Washington does have some state-specific protections; SHIBA (the state's SHIP) can walk you through what applies to your situation.

Rate-adjustment season: how to check what's changing

Medigap premiums aren't set in Washington through the fall enrollment period. Instead, insurers file proposed rate changes with the Washington Office of the Insurance Commissioner (OIC), which reviews them. New rates typically take effect on the policy's anniversary or a date the insurer specifies in the filing.

To see what's happening with your policy for 2026:

1. Look at your renewal notice from your insurer — it will state the new premium and the effective date. 2. Check the OIC's Medigap rate guide, which lists filed rates by insurer and plan letter for Washington ZIP codes. 3. Compare the same plan letter across insurers on the Medicare.gov Medigap policy search. Because plan letters are standardized, a Plan G is a Plan G — the benefits are identical from company to company; only the price and the insurer differ.

Insurers entering or leaving Washington

Medigap carriers do occasionally enter or exit the Washington market, or stop selling certain plan letters to new applicants. We don't have a confirmed 2026 list of insurer changes to share here, and we won't name carriers we can't verify. The reliable places to check:

• Medicare.gov Medigap policy search — enter your Seattle ZIP code to see every insurer currently offering Medigap in your area.
• Washington OIC — publishes the Medigap rate guide and can confirm which companies are approved to sell in the state.
• SHIBA (Washington's SHIP) — free, unbiased counseling; 1-800-562-6900.

If you already have a policy and your insurer is exiting or dropping your plan, you may qualify for a guaranteed-issue right to switch — but the timing rules are strict, so call SHIBA or 1-800-MEDICARE as soon as you get the notice.

A quick note on Part D, since it often comes up

Medigap doesn't cover prescription drugs, so most people pair it with a stand-alone Part D plan. A few 2026 program facts worth knowing: the Part D out-of-pocket cap is $2,100, the maximum Part D deductible is $615, and the coverage gap is gone — Part D now has three phases. The Medicare Prescription Payment Plan lets you spread drug costs across the year in monthly installments if that helps your budget. IRMAA surcharges on Part B and Part D begin above $109,000 in income for a single filer in 2026.