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Your Medigap open enrollment period in Washington
By Vadim Marusin, licensed Medicare insurance agent in Washington (WAOIC #1365574). Insurer data checked against the state chart current as of October 8, 2026.
You get one six-month window when every Medigap insurer must accept you, whatever your health. In Washington, the state's switching rule softens the cost of missing it, but only if you're already on Medigap.
When it starts
Your Medigap open enrollment period lasts six months and starts on the first day of the month in which you're both 65 or older and enrolled in Medicare Part B. It happens once in your life and can't be restarted.
Examples:
- Your birthday is June 18 and your Part B starts June 1. Your window runs June 1 through November 30.
- You turn 65 in March but keep your employer's group plan and don't take Part B until you retire in October. Your window runs October 1 through March 31 of the next year.
- You enroll in Part B in January of the year you turn 65 in April. Your window starts April 1, the month you turn 65.
What it protects
During those six months, any insurer selling Medigap in Washington must:
- sell you any Medigap plan it offers in your county,
- without asking health questions or using your health to set the price,
- and without making you wait for coverage of pre-existing conditions if you had at least six months of prior creditable coverage (Washington caps any waiting period at three months anyway).
When to apply
You can apply up to six months before your Part B start date. Most people apply two to three months ahead so the policy starts the same day as Part B and there's no gap.
If you miss it
Outside the window, an insurer can ask health questions and decline you, unless:
- You already have Medigap Plan B through N. Washington lets you switch to any other insurer's Plan B through N at any time with no health questions. Plan A can switch to Plan A. See switching Medigap plans in Washington.
- You have a guaranteed-issue right, such as losing employer coverage or leaving a Medicare Advantage plan within your trial period. See guaranteed-issue rights.
- You apply to the state-sponsored HCA Premera Plan G during its enrollment windows. See the HCA Premera Plan G.
If none apply and you're turned down for health reasons, Washington's high-risk pool may help. See if you're declined for Medigap.
Under 65 on Medicare
If you have Medicare because of a disability, Washington doesn't give you a Medigap open enrollment until you turn 65. At 65 you get a fresh six-month window. Until then, options are limited; see Medigap under 65.
Common questions
Is there an annual Medigap open enrollment in Washington?
No. Medicare's fall open enrollment (October 15 to December 7) is for Medicare Advantage and Part D plans, not Medigap. Washington doesn't need one, because people with Medigap Plan B through N can switch at any time.
Should I take Part B at 65 just to start my Medigap window?
Not if you have group coverage from current employment that counts as primary. Starting Part B starts the clock on your one-time Medigap window. Talk to your employer's benefits office first; see employer coverage and Medigap.
Can an insurer charge me more because I'm older when my window opens late?
No. Washington's community rating means your premium doesn't depend on your age.