Medicare
Medicare Open Enrollment 2027 in California: Dates, Plan Changes, and Checklist
Medicare Open Enrollment for 2027 runs from October 15 through December 7, 2026. During this annual period, people with Medicare can review their current coverage and make certain changes for January 1, 2027.
Even if you are satisfied with your current plan, reviewing the 2027 materials is worthwhile. Premiums, deductibles, provider networks, prescription formularies, pharmacy arrangements, prior-authorization rules, and supplemental benefits can change from one plan year to the next. The right comparison is based on your own doctors, prescriptions, budget, and coverage needs—not on one benefit or premium alone.
Key Medicare Open Enrollment dates for 2027 coverage
- By September 30, 2026: Medicare Advantage and Part D plans generally send members an Annual Notice of Change (ANOC) describing changes for the coming year.
- October 1, 2026: You can begin reviewing 2027 plan information on Medicare’s Plan Compare tool as information becomes available.
- October 15–December 7, 2026: Medicare Open Enrollment. The plan must receive your enrollment request by December 7.
- January 1, 2027: Changes made during Open Enrollment generally take effect.
What can you change during Medicare Open Enrollment?
According to Medicare, the choices available during Open Enrollment depend on your current coverage. In general, you may:
- switch from Original Medicare to a Medicare Advantage plan;
- switch from Medicare Advantage back to Original Medicare;
- change from one Medicare Advantage plan to another;
- join, switch, or drop a Medicare drug plan; or
- choose a Medicare Advantage plan with or without drug coverage, when eligible.
If you return to Original Medicare, consider whether you need a separate Part D plan. You may also want Medicare Supplement Insurance (Medigap), but federal guaranteed-issue rights and California rules do not mean that every Medigap option is available without medical underwriting at every time. Confirm your rights and application requirements before leaving existing coverage.
What should you review before choosing a 2027 plan?
1. Read your Annual Notice of Change
Do not assume your current plan will work the same way in 2027. Review changes to premiums, deductibles, copays, covered services, drug coverage, service area, and plan rules. Keep the ANOC with your other plan documents so you can compare the current year with 2027. For a section-by-section review, see what to check in your 2027 Medicare Annual Notice of Change.
2. Confirm every doctor, hospital, and medical group
Provider directories can change, and a doctor’s participation in one plan does not confirm participation in another. Check the 2027 plan directory and confirm directly with the provider’s office. In California, also verify the medical group or independent practice association when it affects access to specialists and facilities.
3. Review each prescription
Prepare a complete medication list with the exact drug name, dosage, quantity, and preferred pharmacy. Check the 2027 formulary, drug tier, copay or coinsurance, prior-authorization requirements, step therapy, quantity limits, and whether your pharmacy is preferred or standard.
4. Compare total annual cost—not just the premium
A $0-premium Medicare Advantage plan is not a $0-cost plan. Compare medical and drug premiums, deductibles, copays, coinsurance, the medical out-of-pocket maximum, prescription costs, and expected use of care. Original Medicare does not have the same annual out-of-pocket limit as Medicare Advantage, so the structures should be compared carefully.
5. Review supplemental benefits and their limits
Dental, vision, hearing, transportation, fitness, over-the-counter allowances, and other supplemental benefits may have networks, frequency limits, dollar limits, or eligibility rules. Confirm the details in the 2027 Evidence of Coverage instead of choosing a plan based only on an advertisement.
6. Check plan quality and service
Star Ratings can help compare plan quality, but they should be considered together with your providers, prescriptions, costs, and service needs. CMS has finalized changes affecting the 2027 Star Ratings methodology, so review the rating displayed for the specific 2027 contract rather than relying on an older rating.
2027 Medicare Open Enrollment checklist
- Your Medicare card and current plan identification cards
- Your 2027 Annual Notice of Change and Evidence of Coverage
- A list of doctors, specialists, hospitals, and medical groups
- A complete prescription list with dosages and pharmacies
- Your expected medical and prescription needs for 2027
- Your monthly budget and estimated out-of-pocket costs
- Questions about referrals, prior authorization, travel, and supplemental benefits
Open Enrollment is not the same as other Medicare enrollment periods
Medicare Open Enrollment (October 15–December 7) allows broad changes to Medicare Advantage and Part D coverage for the following year.
Medicare Advantage Open Enrollment (January 1–March 31) is only for people already enrolled in a Medicare Advantage plan. During that period, a person may generally make one change to another Medicare Advantage plan or return to Original Medicare and join a separate drug plan. It cannot be used by someone with Original Medicare to join Medicare Advantage.
The General Enrollment Period (January 1–March 31) concerns enrollment in Medicare Part A and/or Part B for certain people who missed another opportunity. It is different from both plan-election periods above. Special Enrollment Periods may be available after qualifying life or coverage events.
Free help reviewing Medicare options
Skyline Benefit can help California Medicare beneficiaries organize their doctors and prescriptions, compare available Medicare Advantage and Part D options, and understand plan differences. There is no additional fee to you for Skyline Benefit’s Medicare plan comparison and enrollment assistance. Enrollment in a plan is not required, and Skyline Benefit does not offer every plan available in every area.
Call (714) 888-5112 or request a Medicare consultation.
Related Medicare guides
- 2027 Medicare Annual Notice of Change: What to Check
- Will My Doctor Be In-Network in 2027?
- California Medicare Prescription Review Checklist
Official Medicare resources
This article provides general educational information and is not a complete description of benefits. Plan availability, premiums, provider networks, formularies, benefits, and rules vary by plan and can change. Review current Medicare and plan documents before making a decision.