How to Change Your Medicare Plan Before the Dec. 7 Deadline

California's average Medicare Advantage premium rises next year while the national average falls, and free county counseling is one phone call.

Your Medicare plan can change its drug list, its copays and its premium on January 1. You have until December 7 to answer, and the window to do it opens October 15. You're wondering whether any of that matters if you like the plan you're on, and it might, because the plan you like is allowed to be a different plan next year.

The work has an order, and the order is what saves the afternoon: the letter your plan had to mail by September 30 comes first, your own prescription list second, the money you may already be entitled to third. Whether to switch comes last. Most people will decide not to, and finding that out takes about twenty minutes.

The four dates

Medicare's own calendar for this fall, published by the Centers for Medicare & Medicaid Services in a state-by-state fact sheet dated September 28, sets out the autumn in four steps. Only one of them is a deadline.

October 1. Medicare's Plan Finder was due to carry 2027 health and drug plan prices by this date, so comparison shopping is already possible.

October 8. The 2027 star ratings — Medicare's own one-to-five quality score for each health and drug plan — are due on Medicare.gov on or around this day.

October 15 to December 7. The open enrollment window itself. Medicare's rule is that the plan must get your request to join by December 7, so the date that counts is the day the plan has it in hand, not the day you posted it.

January 1. Whatever you chose starts. Whatever you didn't choose also starts, in next year's version. The federal fact sheet is blunt about the one thing nobody has to do: people who want to keep their current Medicare coverage don't need to re-enroll.

First: the letter that had to arrive by September 30

Every Medicare Advantage plan and every Part D drug plan — Part D is the prescription half of Medicare, sold either on its own or folded into an Advantage plan — has to put one document in your mailbox before open enrollment starts. It's called the Annual Notice of Change, and under the federal rules at 42 C.F.R. 422.111 and 423.128 the plan must get it to members no later than September 30, fifteen days before the window opens.

That letter is the only piece of paper that tells you what your own plan is doing next year: the new premium, the new deductible, the new copays, and the drugs it has added to or dropped from its list. Read the drug list before you read the premium. A plan that holds its price and drops one of your prescriptions has raised your costs, and the premium line won't show it.

If the envelope went out with the recycling, the same comparison is on Medicare's Plan Finder, and 1-800-MEDICARE is staffed 24 hours a day, seven days a week.

Second: price your prescriptions, not the premium

Two numbers in the drug benefit move next year, and both move against you. No Medicare drug plan may charge a deductible of more than $700 in 2027, up from $615 this year. And the annual cap on what you pay out of pocket for covered Part D drugs — the point at which your share drops to nothing for the rest of the calendar year — rises from $2,100 in 2026 to $2,400 in 2027.

So the useful exercise isn't comparing monthly premiums. It's typing your actual prescriptions, with doses, into the Plan Finder and reading the annual total each plan quotes you, because a $12 premium looks better than a $40 one right up to the first refill of a drug the cheaper plan stopped covering.

One more option exists for people whose costs land in one brutal month: the Medicare Prescription Payment Plan spreads Part D out-of-pocket costs across the calendar year in level installments. Medicare's own page on it is unusually frank, and worth quoting exactly — it “doesn't save you money or lower your drug costs.” It moves them. For a fixed income, moving them is sometimes the whole point.

California is the state where the premium went the other way

Nationally this was the year Medicare Advantage got cheaper on paper. CMS projects the weighted average monthly premium across all Advantage plans falling from $14.37 in 2026 to $12.00 in 2027, a drop of 16.5 percent, with the drug portion inside those plans falling 38 percent, from $11.32 to about $7.

California didn't get that. The state's own page in the federal fact sheet puts the average monthly Advantage premium here at $14.12 in 2027, up from $13.77 in 2026. The number of Advantage plans sold in California drops from 402 to 394, against a national count holding almost flat at about 5,532. Access isn't the problem: 99.64 percent of the 7,243,867 Californians on Medicare can buy an Advantage plan, and the same 99.64 percent can buy one with a $0 premium.

Los Angeles County has more riding on those plans than most places in the country. CMS's own monthly enrollment file counted 1,714,558 people on Medicare in the county in June 2026, of whom 980,549 were in a Medicare Advantage or similar private plan and 734,009 were in Original Medicare. We ran that division: 57 percent of the county's Medicare population is in a private plan, while CMS projects Advantage will hold 47.4 percent of Medicare nationally in 2027. The plans whose premiums rose here cover the majority of Angelenos on Medicare.

Third: if your drug plan is a stand-alone, California has ten of them

542,956 people in Los Angeles County carried a stand-alone prescription drug plan in June — Original Medicare on one card, drug coverage bought separately on another. For 2027 the federal fact sheet lists 10 stand-alone drug plans available in California, the cheapest at $5.30 a month. Ten is the whole market, which makes the comparison short and the stakes high: one plan dropping a drug leaves nine alternatives, not ninety.

The good news in that section is real and it is specific. CMS says 100 percent of Californians holding a stand-alone drug plan have access to a plan with a lower premium than the one they paid in 2026. Nationally the average stand-alone premium barely moves, from $35.09 to about $36.

Read that against one line further down the federal announcement. The Part D Premium Stabilization Demonstration — the federal subsidy that has been holding stand-alone drug premiums down, already narrowed for 2026 — is being discontinued in 2027. A cheaper plan is available; the floor under the one you have is being removed.

Fourth: the help that about half of eligible people never claim

Before you compare a single premium, check whether you should be paying one at all. Two federal programs cut Medicare costs for people with low incomes, and the federal fact sheet states the failure rate plainly: of the people eligible for the Medicare Savings Programs, which help pay Medicare premiums and may also pay deductibles, coinsurance and copayments, only about half are enrolled.

The drug-side program is called Extra Help. Medicare's own eligibility page sets the 2026 test at an annual income below $23,940 for one person or $32,460 for a married couple living together, and resources below $18,090 or $36,100. Qualify and the plan premium and the deductible are both $0, generics run up to $5.80 and brand-name drugs up to $14.40, and once your drug costs reach $2,400 you pay nothing more that year.

Two numbers say how much of this is unclaimed locally. Across California, 32.27 percent of people with a stand-alone drug plan get Extra Help. In Los Angeles County, 538,636 people were enrolled in both Medicare and Medi-Cal in June, and Medicare's page says full-benefit Medicaid coverage — Medi-Cal, here — brings Extra Help automatically. Not all 538,636 hold the full benefit. The gap between the two figures is where the unclaimed money sits.

If you carry a Medigap policy, your birthday is a window of its own

Medigap is the private supplement sold alongside Original Medicare to cover what Medicare doesn't, and California gives its holders a right that most states don't. The Department of Insurance states the rule this way: if you already have a Medigap policy, you have 60 days of open enrollment following your birthday each year in which you can buy a new one “without a medical screening or a new waiting period.”

The catch is in the same sentence. The new policy must carry the same or lesser benefits than the one you're leaving, so the birthday rule is a tool for moving sideways to a cheaper insurer, not for upgrading. It also runs on your own calendar rather than Medicare's, which means a December 7 that passes without action doesn't close it.

Free help in Los Angeles County is a phone call

California runs a counseling service for exactly this decision, and it costs nothing. The Health Insurance Counseling and Advocacy Program — HICAP — offers what the state Department of Aging describes as free, confidential one-on-one counseling on Medicare enrollment and coverage options, plus help with appeals and denied claims. Its statewide line is 1-800-434-0222.

In Los Angeles County the program is run by the Center for Health Care Rights, at 4601 Wilshire Boulevard, Suite 160. The county's Aging and Disabilities Department publishes the intake line as 1-800-510-2020 and says appointments are required: roughly 45 minutes for a first phone appointment, about an hour in person, with virtual sessions on request. Counseling is offered in English, Spanish, Japanese, Cantonese and Mandarin.

Book that appointment in October rather than December. The county's own instruction is that this runs by appointment, and the appointments in front of a December 7 deadline are the ones that fill.

If December 7 goes by

There is a second window, and it is narrower than people expect. Between January 1 and March 31, Medicare's own fact sheet on enrollment periods allows anyone already in a Medicare Advantage plan to make one change: switch to a different Advantage plan, or drop it and return to Original Medicare, in which case you may also join a stand-alone drug plan. The change takes effect the first of the month after the plan gets your request.

What that window can't do is the part that strands people. It can't move you from Original Medicare into a Medicare Advantage plan, and it can't move you from one stand-alone drug plan to another. For those two decisions, December 7 is the whole year.