Benefits Open Enrollment: Dates, Choices, and Mid-Year Changes

Benefits open enrollment is the yearly window when you pick or update your health insurance, tax-advantaged accounts, and other workplace benefits for the coming plan year. For 2026 Marketplace coverage, the window runs from November 1, 2025, through January 15, 2026. Employer plans set their own calendars, usually in the fall. The details that trip people up differ by coverage type, and a few weeks of inattention can lock you into the wrong plan for a full year.

2026 Marketplace Dates

The federal Health Insurance Marketplace opens November 1, 2025, and closes January 15, 2026.¹ When you enroll decides when coverage starts:

Enroll by December 15, 2025: coverage begins January 1, 2026.
Enroll December 16 through January 15: coverage begins February 1, 2026.²

That gap matters more than people expect. Waiting until after the holidays means a full month of January with no insurance before the new plan kicks in. If you take an ongoing prescription or have a procedure planned for early in the year, December 15 is the date to circle.

Employer Plan Windows

Most employers run open enrollment in the fall, typically for two to four weeks. The exact dates follow the company’s plan year, which may or may not match the calendar year. There’s no standardized national schedule. Your employer will communicate the dates through email, an HR portal, or a mailing.

Window length varies. Some large employers give a full month; others compress it into ten business days. Treat the first email as the start of a countdown, not a reminder you can file for later.

What You Can Choose

Open enrollment covers more than health insurance. The exact menu depends on whether you’re enrolling through an employer or the Marketplace.

Health insurance: PPO, HMO, and high-deductible plans with different trade-offs between premiums, provider flexibility, and out-of-pocket costs.
Dental and vision: usually separate elections covering cleanings, exams, glasses, and contacts. Not included in most Marketplace health plans.
Life insurance: employer plans often provide a small base policy for free and let you buy additional coverage. Enrolling during open enrollment frequently lets you add coverage without answering health questions, which is a real advantage if you have pre-existing conditions.
Disability insurance: short-term and long-term policies that replace part of your income if illness or injury keeps you from working.

The Marketplace focuses on health insurance. Employer plans bundle the supplemental options alongside it.

FSAs and HSAs: Different Rules, Easy to Confuse

These two accounts both let you pay for medical costs with pre-tax money, but they follow different rules. Mixing them up is one of the most common enrollment mistakes.

Flexible Spending Accounts

An FSA lets you set aside pre-tax money for eligible medical expenses. For 2026, the health care FSA contribution limit is $3,400, up from $3,300 in 2025. You must actively elect your FSA contribution every year during open enrollment. It does not automatically renew.³

FSAs are generally use-it-or-lose-it, but your plan may offer one of two relief options (never both):

Grace period: up to two and a half extra months after the plan year ends to spend remaining funds on eligible expenses.
Carryover: up to $680 of unused funds can roll into the next plan year for 2026.³

If your plan offers neither option, any unspent balance disappears at year-end. Check which arrangement your employer provides before deciding how much to contribute. Overestimating is the classic FSA mistake: people set aside $2,000, spend $1,400, and lose the rest.

Health Savings Accounts

HSAs are available only if you’re enrolled in a qualifying high-deductible health plan. For 2026, the HDHP must carry a minimum annual deductible of $1,700 for individual coverage or $3,400 for family coverage, with out-of-pocket maximums capped at $8,500 and $17,000. The 2026 HSA contribution limits are $4,400 for individuals and $8,750 for families.⁴

Unlike FSAs, HSA funds roll over indefinitely. There’s no use-it-or-lose-it pressure, and your balance stays with you if you change jobs or plans.³ HSA elections typically carry forward without annual re-election, though you can adjust the contribution amount during open enrollment.

If You Do Nothing

Doing nothing produces different results depending on where your coverage comes from.

Employer Plans: Passive or Active

Some employers use passive enrollment, where your current selections carry forward if you take no action. Your health plan, dental coverage, and life insurance renew at the new year’s rates. Other employers require active enrollment, meaning you must affirmatively select your benefits each year. Under active enrollment, failing to make a selection means you start the year with no coverage at all.

Even under passive enrollment, flexible spending accounts never carry over. You must re-elect your FSA contribution every year, or no money is set aside.

Marketplace: Automatic Re-Enrollment

If you already have a Marketplace plan and do nothing, the Marketplace will automatically re-enroll you in the same plan, or a comparable one if yours is discontinued, to prevent a gap in coverage.⁵ That’s a safety net, but a lazy one. Premiums, provider networks, and drug formularies change every year. The plan you’re rolled into could cost significantly more or drop a doctor you rely on. Twenty minutes of comparison can save hundreds of dollars.

Automatic re-enrollment only applies to current Marketplace enrollees. If you’re signing up for the first time and miss January 15, you’ll wait until the next open enrollment period or until you qualify for a special enrollment period.

Federal and State Penalties

The federal tax penalty for not having health insurance ended after 2018.⁶ A handful of states enforce their own individual mandates with tax penalties for residents who lack minimum essential coverage. If you live in one of those states, skipping enrollment can cost you at tax time on top of any uninsured medical bills.

What to Have Ready Before You Start

Hunting for a birth certificate at 11 p.m. on the deadline is avoidable. Gather these before the window opens:

Full legal names, Social Security numbers, and dates of birth for yourself and every dependent you plan to cover.⁷
Marriage or birth certificates if you’re adding a new spouse or child for the first time.
Beneficiary details (names, addresses, relationships) for life insurance and accidental death policies. Most plans allow primary and contingent beneficiaries.
Projected household income if enrolling through the Marketplace. It determines eligibility for premium tax credits and cost-sharing reductions.
Your current plan details, so you can compare meaningfully.

Federal law requires health plans that offer dependent coverage to extend it to children until they turn 26, regardless of marital status, student status, employment, or financial independence.⁸ Plans are not required to cover a dependent’s children, so grandchildren don’t qualify under this rule.

Save the confirmation statement the system generates after you submit. It lists your chosen plans, covered dependents, premium amounts, and effective dates. If your insurance card doesn’t arrive on time, your payroll deductions look wrong, or a provider says you’re not in their system, that confirmation is the fastest route to a fix. A screenshot works as a backup.

Changing Coverage Mid-Year

Outside open enrollment, you can only change coverage if you have a qualifying life event. Common triggers:

Marriage, divorce, or legal separation⁹
Birth, adoption, or foster care placement of a child
Loss of other health coverage (leaving a job, aging out of a parent’s plan at 26, losing Medicaid or CHIP)
Moving to a new ZIP code that changes your plan options
A change in household income that affects Marketplace subsidy eligibility

How long you have depends on the plan. Employer-sponsored group health plans must give you at least 30 days from the qualifying event to request a change.¹⁰ Marketplace plans generally give you 60 days. If you lost Medicaid or CHIP specifically, you get 90 days.¹¹

The Marketplace will ask for documents proving the event and its date: a letter from a former employer showing coverage end date, a birth certificate, adoption paperwork. You have 30 days after picking a new plan to submit them. If you don’t have formal documentation, the Marketplace will accept a letter of explanation and review it case by case.

Working Past 65: Medicare and Open Enrollment

If you’re still working past 65, open enrollment forces you to think about how employer coverage and Medicare interact. Getting this wrong can mean permanent premium penalties or unexpected coverage gaps.

Which plan pays first depends on employer size. If the company has 20 or more employees, your group health plan is primary and Medicare pays second. If it has fewer than 20, Medicare pays first.¹² That distinction shapes whether delaying Medicare enrollment makes financial sense.

Delay Medicare Part B without qualifying employer coverage to justify the gap and you’ll pay a 10% premium surcharge for every 12-month period you were eligible but didn’t enroll. The surcharge is permanent. It applies every month for as long as you have Part B.

HSA holders face another wrinkle. You cannot contribute to an HSA once enrolled in any part of Medicare.³ Because Medicare Part A provides up to six months of retroactive coverage, stop HSA contributions at least six months before your planned Medicare start date to avoid a tax penalty on excess contributions. You can still withdraw from your existing HSA tax-free for qualified medical expenses after Medicare begins. You just can’t add new money.

Fixing Enrollment Errors

If something goes wrong with your Marketplace enrollment, such as a plan selection that didn’t process, a dependent left off coverage, or a subsidy determination that looks incorrect, you have 90 days from the date of the eligibility notice to file an appeal.¹³ You can file online through your Marketplace account, by fax, or by mail.

For employer plan errors, the process runs through your HR department or benefits administrator. Start with a written description of the problem and attach your enrollment confirmation. Most employer plans are required to have a formal grievance procedure, and putting the issue in writing creates a paper trail that matters if the dispute escalates.

1
Centers for Medicare & Medicaid Services. Marketplace 2026 Open Enrollment Fact Sheet
2
HealthCare.gov. Enrollment Dates and Deadlines
3
Internal Revenue Service. Publication 969 – Health Savings Accounts and Other Tax-Favored Health Plans
4
Internal Revenue Service. Revenue Procedure 2025-19
5
HealthCare.gov. Automatic Re-Enrollment Keeps You Covered
6
HealthCare.gov. Exemptions From the Fee for Not Having Coverage
7
HealthCare.gov. Get Ready to Apply for or Re-Enroll in Your Health Insurance Marketplace Coverage
8
eCFR. 45 CFR 147.120 – Eligibility of Children Until at Least Age 26
9
HealthCare.gov. Special Enrollment Period
10
eCFR. 29 CFR 2590.701-6 – Special Enrollment Periods
11
HealthCare.gov. Send Documents to Confirm a Special Enrollment Period
12
Medicare.gov. Who Pays First?
13
Centers for Medicare & Medicaid Services. Marketplace Appeals Job Aid