When a hospital stay ends and a loved one needs more recovery time than they can safely get at home, a skilled nursing facility (SNF) is often the next stop. Original Medicare’s rules for that benefit are well established: up to 100 days per benefit period, with cost-sharing that increases the longer the stay goes. Medicare Advantage plans have to offer that same benefit, but have to offer the same benefit doesn’t mean the experience of using it looks the same. This guide walks through how the 100-day structure works, then focuses on the specific places where a Medicare Advantage plan’s rules diverge from Original Medicare’s, the parts families are most likely to be caught off guard by during a hospital discharge.
For a broader look at how Medicare Advantage handles SNF care alongside assisted living, home health, and rehab, see Medicare Advantage and Senior Care Coverage. This article goes deeper specifically on the 100-day SNF benefit and how MA plans manage it.
The 100-Day Rule: How It Works Under Original Medicare
Both Original Medicare and Medicare Advantage are built on the same underlying SNF benefit structure established by Medicare Part A. Understanding that baseline first makes it easier to see exactly where MA plans introduce their own rules.
- Qualifying hospital stay: a person generally needs at least three consecutive days as an admitted hospital inpatient (not observation status) before Medicare will cover a SNF stay.
- Timing: admission to the SNF typically needs to happen within 30 days of leaving the hospital.
- Medical necessity: a physician has to certify that the person needs daily skilled nursing or therapy services that can only be provided in a SNF setting.
- Days 1 through 20: covered in full, with no daily cost to the patient.
- Days 21 through 100: a daily coinsurance applies, $217 per day in 2026, unless a Medigap policy or other supplemental coverage picks up the difference.
- Day 101 and beyond: Medicare coverage ends and the patient is responsible for the full cost of any continued stay.
This benefit period resets after 60 consecutive days without inpatient hospital or SNF care, so a new illness or injury later in the year can open up a fresh 100 days. Families researching the foundational version of this benefit can see Senioridy’s guide to Medicare coverage for skilled nursing facility care for the full Original Medicare picture.
What Medicare Advantage Plans Are Required to Match
Medicare Advantage plans cannot offer less than Original Medicare for SNF care. By law, an MA plan has to cover the same 100-day benefit, for the same medically necessary skilled nursing and rehabilitation services, and cannot impose a yearly dollar limit on it. A plan also cannot charge more in total cost-sharing for SNF care than Original Medicare’s standard amounts would add up to over a comparable stay.
Where things change is not whether the benefit exists. It is how a specific plan structures the path to using it.
Four Ways Medicare Advantage Handles SNF Coverage Differently
1. The Three-Day Hospital Stay May Be Waived
Original Medicare’s three-day inpatient rule is fixed. Many Medicare Advantage plans, however, have CMS approval to waive it, meaning a person could be admitted directly to a SNF, or transferred after a shorter hospital stay, and still have it covered. This varies plan by plan and isn’t guaranteed. Families should check the plan’s Evidence of Coverage or call member services directly to ask whether their specific plan waives the three-day rule before assuming either way.
2. Prior Authorization Is the Norm, Not the Exception
This is the single biggest practical difference. Original Medicare rarely requires prior authorization before covering a SNF stay. Medicare Advantage takes the opposite approach: the vast majority of MA enrollees are in plans that require prior authorization for skilled nursing facility admission, while only a sliver of Original Medicare requests go through that process at all. In practice, this means a hospital discharge planner usually has to get sign-off from the MA plan before finalizing a SNF placement, a step that can add time, and occasionally delay, to a transition that Original Medicare beneficiaries move through without that extra approval.
Federal rules that took effect in 2026 require MA plans to decide expedited prior authorization requests within 72 hours and standard requests within 7 calendar days, and to give a specific reason when a request is denied. Federal oversight reviews have also found that when SNF prior authorization denials are appealed, the large majority get overturned, which suggests some initial denials may be more about process than medical necessity. Families facing a denial have the right to appeal, and doing so is often worthwhile, with help available for free through a SHIP counselor.
3. Network Rules Can Limit Where Care Happens
Original Medicare lets a beneficiary use any Medicare-certified SNF with an open bed. Medicare Advantage plans generally route coverage through a network. HMO-style MA plans tend to have the tightest restrictions, sometimes with no out-of-network SNF coverage at all outside an emergency. PPO-style plans usually allow out-of-network care, but at a higher cost-sharing level.
For emergency admissions, MA plans are required to cover care at the nearest appropriate facility regardless of network status. For planned or post-hospital transfers, though, verifying network status in advance matters. The plan’s online provider directory, or a direct call to member services, is more reliable than asking a hospital discharge planner to confirm it. Families can cross-check facility quality using Medicare’s Care Compare tool alongside Senioridy’s skilled nursing home directory and SNF short-term rehab directory.
4. Cost-Sharing Structure Is Plan-Specific
Original Medicare’s $217-per-day coinsurance for days 21 through 100 (2026 figure) is fixed nationwide. Medicare Advantage plans set their own copay or coinsurance structure for SNF care, and it is not required to mirror Original Medicare’s day-by-day pattern. Some plans charge a flat copay for an initial block of days and nothing afterward; others use a different daily schedule entirely. What MA plans cannot do is charge more, in total, than Original Medicare’s standard cost-sharing would amount to for a comparable stay. Every MA plan also caps total annual out-of-pocket spending for in-network care, $9,250 in 2026 at the federal maximum, after which the plan covers 100% of covered services for the rest of the year. Original Medicare has no such cap on its own.
What Stays the Same Either Way
- Custodial, long-term nursing home care (help with daily living needs rather than skilled medical care) is excluded under both Original Medicare and Medicare Advantage.
- The 100-day ceiling per benefit period applies under both.
- Both require the underlying medical necessity standard: a physician-certified need for daily skilled nursing or therapy that only a SNF setting can provide.
- Appeal rights exist under both, though the process for MA runs through the plan rather than Medicare directly.
Questions to Ask Before a Discharge Happens
Sorting through MA SNF rules during a hospital discharge is far harder than doing it in advance. Families with a parent on Medicare Advantage may want to ask the plan these questions before a crisis, not during one:
- Does this plan waive the three-day hospital stay requirement for SNF admission?
- Does this plan require prior authorization for SNF stays, and what is its typical turnaround time?
- Is the plan an HMO or a PPO, and what does that mean for out-of-network SNF coverage?
- Which SNFs in the area are in-network, confirmed directly with the plan rather than assumed from a facility’s general reputation?
- What is the plan’s specific daily cost-sharing structure for SNF days, and how does it compare to the $217-per-day Original Medicare standard?
For a fuller comparison of how Medicare Advantage handles SNF coverage alongside assisted living, home health, and other senior care settings, see Medicare Advantage and Senior Care Coverage. Families still deciding between Medicare Advantage and Original Medicare in the first place may also want to start with Medicare Advantage vs. Original Medicare: Which Is Better for Seniors Who Need Care?.
Find Skilled Nursing Care Near You
Whether a loved one is on Original Medicare or a Medicare Advantage plan, finding the right facility matters as much as understanding the coverage rules. Search Senioridy’s skilled nursing home directory or SNF short-term rehab directory to compare options and connect directly with providers in your area.
Sources: Medicare.gov — Skilled Nursing Facility Care | CMS 2026 Medicare Parts A & B Premiums and Deductibles | KFF: Medicare Advantage in 2026
This article is for informational purposes only and does not constitute legal, financial, or medical advice. Medicare and Medicare Advantage coverage rules, cost figures, and program details are subject to change and can vary by plan and state. Medicare Advantage plan rules may differ from Original Medicare in the ways described above. For free, personalized Medicare guidance, contact your State Health Insurance Assistance Program (SHIP) counselor at shiphelp.org, available in every state at no cost. Always confirm current coverage details with your specific plan.