When Your Parent Turns 65: The Adult Child's Medicare Checklist

If your parent is turning 65, they have a 7-month window to enroll in Medicare — and missing it costs them a permanent penalty on their monthly premiums for the rest of their life, according to CMS enrollment rules.

This guide walks you through exactly what to do, when to do it, and what to watch out for — written for the adult child handling it, not the senior on the plan.

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The 7-month window (and why it matters)

Medicare's Initial Enrollment Period (IEP) opens 3 months before the month your parent turns 65, includes the birthday month itself, and closes 3 months after. That's 7 months total, per Medicare.gov.

Miss it, and your parent faces a 10% premium penalty for every 12 months they were late — permanent, for life. The CMS Part B penalty page confirms this has no expiration.

The only exception: if your parent is still covered by employer insurance from an active job (not retirement), they can delay without penalty and use a Special Enrollment Period when that coverage ends.

The single most common mistake: Waiting until the birthday month to start. Enrolling during the 3 months before the birthday month means coverage starts on the first day of the birthday month — not delayed by up to 3 months.

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Step 1 — Figure out what they already have (2–3 months before 65)

Before you do anything, find out your parent's current insurance situation:

• Still working with employer coverage? Their HR department can confirm whether the plan is "creditable" — meaning it's equivalent to Medicare and delays the penalty clock.
• On a spouse's employer plan? Same question — creditable coverage delays enrollment.
• On COBRA, retiree coverage, or marketplace insurance? These do not count as creditable. Enroll in Medicare on time.
• On Medi-Cal (California Medicaid)? They may be automatically enrolled in Parts A and B at 65, but may still need to choose a Medicare Advantage or Part D drug plan.

If there's any doubt, call Social Security at 1-800-772-1213 and ask directly whether current coverage counts as creditable. This is a free call with no obligation.

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Step 2 — Enroll in Original Medicare (Parts A and B)

When: 3 months before the birthday month for the earliest coverage start date.

How: Online at SSA.gov, by phone at 1-800-772-1213, or in person at a local Social Security office.

What you're enrolling in:

• Part A (hospital insurance) — Premium-free for most people who worked and paid Medicare taxes for at least 10 years (40 quarters), per CMS Part A eligibility rules.
• Part B (medical insurance, doctor visits) — The 2026 standard premium is $185.00/month, per the CMS Medicare costs fact sheet. Higher earners pay more (IRMAA surcharge).

One thing most guides miss: Original Medicare alone has no out-of-pocket maximum. A major hospitalization could cost tens of thousands. Almost everyone needs additional coverage on top of Parts A and B.

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Step 3 — Choose coverage beyond Parts A and B

"The biggest source of confusion I see is families thinking Original Medicare is complete coverage. It's not — it's a foundation. Whether you add a supplement or an Advantage plan depends entirely on your parent's doctors, medications, and risk tolerance. There's no universal right answer."

— Gregory Song, CA-Licensed Insurance Agent, Filial Medicare Advisors

There are two paths, and they work very differently:

Path 1 — Medicare Advantage (Part C)

A private insurance plan that replaces Original Medicare. Usually bundles drug coverage (Part D). Plans are HMO or PPO, and benefits vary by plan and county — many include dental, vision, hearing, and transportation.

• Most plans have $0 or low monthly premiums in California
• Tradeoff: Network restrictions. Out-of-network care costs more or may not be covered.
• Important for 2026: Several major California networks — including Scripps Health, UC San Diego Health (for some plans), and Sutter Health (for UHC plans in NorCal) — have dropped out of Medicare Advantage contracts. Per a February 2026 JAMA research letter by Meiselbach et al., approximately 2.9 million MA enrollees nationally faced forced disenrollment for 2026 — 10x the historical baseline. Check your parent's doctors before picking a plan.

Path 2 — Original Medicare + Medigap + Part D

Keep Original Medicare and add a Medigap policy to cover gaps (deductibles, coinsurance, out-of-pocket costs). Add a separate Part D drug plan for prescriptions.

• Most flexible — any doctor who accepts Medicare, anywhere in the country
• Tradeoff: Medigap premiums in California typically run $150–$300+/month depending on plan type and age at enrollment, per California Department of Insurance Medigap rate data
• Key rule: The best time to buy Medigap is during the Open Enrollment Period — the 6 months starting the month your parent turns 65 and is enrolled in Part B. Insurers cannot deny coverage or charge more based on health history during this window. After it closes, they can.

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Step 4 — Add Part D (prescription drug coverage)

If your parent chooses Original Medicare + Medigap (not Medicare Advantage, which usually includes drugs), they need a separate Part D plan.

When: Same 7-month IEP as Parts A and B.

Why it matters: Skipping Part D when first eligible creates a 1% penalty per month added to the premium permanently — even if they take no medications today, per CMS Part D late enrollment penalty rules.

To compare plans: Medicare Plan Finder lets you enter medications and ZIP code to see actual out-of-pocket drug costs per plan.

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Step 5 — Check for California-specific programs

California has programs that can significantly reduce costs for lower-income beneficiaries:

• Dual eligible (Medi-Cal + Medicare): Qualifying seniors may be eligible for a D-SNP — a Medicare Advantage plan that coordinates both coverages, often with $0 premiums and reduced cost-sharing. See Covered California's Medi-Cal eligibility guide.
• HICAP: California's free Medicare counseling program (aging.ca.gov) — unbiased, no commission, staffed by trained volunteers. Good for a second opinion.
• PACE: Program of All-inclusive Care for the Elderly — for seniors 55+ needing nursing-home-level care who want to stay at home. Available in select California counties.

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The most common mistake adult children make

Picking a plan based on premium alone.

A $0-premium Medicare Advantage plan sounds free — but if your parent's cardiologist isn't in network, or their hospital left the plan mid-year, the out-of-pocket exposure can be significant. The Kaiser Family Foundation tracks Medicare Advantage out-of-pocket maximums by plan — they can reach $8,850 in-network in 2026.

The right question isn't "what's cheapest?" It's: Does this plan cover their doctors, their hospital, and their medications — at a cost the family can manage?

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Quick reference timeline

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Frequently asked questions

What happens if my parent misses the Medicare enrollment deadline?

They face a permanent 10% Part B premium penalty for every 12-month period they were late. This surcharge lasts as long as they have Medicare — it never goes away.

Can I enroll in Medicare on my parent's behalf?

You can help gather information and fill out the application, but your parent (or their legal power of attorney) must sign and submit the enrollment. Call Social Security at 1-800-772-1213 to ask about POA documentation requirements.

Does my parent need Medicare if they're still on my employer's plan?

If your parent is covered by an active employer plan (from someone still working), they can delay Part B without penalty. Retired employer coverage and COBRA do not count — they must enroll on time.

What's the difference between Medicare Advantage and Original Medicare?

Original Medicare (Parts A and B) is government insurance with no network restrictions but no out-of-pocket maximum. Medicare Advantage is a private plan that replaces Original Medicare — usually with lower premiums but network restrictions. Most Advantage plans include drug coverage; Original Medicare requires a separate Part D plan.

When is the best time to buy a Medigap policy?

During the 6-month Open Enrollment Period that starts the month your parent turns 65 and is enrolled in Part B. During this window, insurers cannot deny coverage or charge more due to health conditions. After it closes, they can.

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We do not offer every plan available in your area. Currently we represent 14 organizations which offer Medicare Advantage, D-SNP, and Prescription Drug Plans in your area. Please contact Medicare.gov, 1-800-MEDICARE (1-800-633-4227, TTY: 711), or your local State Health Insurance Assistance Program (SHIP) to get information on all of your options.