What is Open Enrollment? Key Dates, Types, and Deadlines for 2026

Open enrollment is the yearly window when you can sign up for, change, or cancel health insurance without needing a qualifying life event. It isn’t one single deadline, though. The ACA Marketplace on HealthCare.gov, Medicare, and employer-sponsored health insurance each run their own open enrollment period on their own calendar.

Here’s where things stand this fall. Medicare open enrollment runs from October 15 to December 7, 2026. ACA Marketplace open enrollment on HealthCare.gov runs from November 1, 2026, to January 15, 2027. Both windows are for 2027 coverage. Most employers hold their own open enrollment in October or November.

In this guide, I’ll walk you through what open enrollment means, the key 2026 dates and deadlines for each type, and what you can do if you miss one.

What is Open Enrollment?

Open enrollment is a set period each year when you can sign up for, change, or cancel health insurance. It applies to ACA Marketplace plans, Medicare, and most employer-sponsored health plans. Outside the window, you can usually only change coverage if you have a qualifying life event, such as marriage, a new baby, or losing other coverage.

The three main types of open enrollment are:

• ACA Marketplace open enrollment: for individuals and families who buy their own coverage through HealthCare.gov or a state exchange.

• Medicare open enrollment: also called the Annual Enrollment Period, when people on Medicare can switch health and drug plans.

• Employer open enrollment: when employees choose or change workplace benefits for the next plan year.

Each open enrollment period has its own dates, rules, and coverage start date. Missing one doesn’t affect the others.

Why Does Open Enrollment Exist?

Open enrollment exists because insurers need people to sign up at set times, not only when they get sick. If anyone could buy coverage the day they needed surgery and drop it afterward, the pool of insured people would skew toward high claims, and premiums would climb for everyone.

A fixed yearly window helps in three ways:

• It keeps premiums more stable.

• It encourages continuous coverage.

• It gives insurers and employers a predictable cycle to set prices, update plan designs, and send out renewal notices.

Open Enrollment Dates for 2026

Open enrollment for 2027 coverage runs from October 15 to December 7, 2026 for Medicare and from November 1, 2026 to January 15, 2027 on HealthCare.gov. If you’re looking for 2026 coverage, the windows for it have already closed: Medicare’s ran from October 15 to December 7, 2025, and HealthCare.gov’s ended on January 15, 2026.

ACA Marketplace Dates

On HealthCare.gov, open enrollment for 2027 plans runs from November 1, 2026 to January 15, 2027. To have coverage on January 1, 2027, you need to pick a plan by December 15, 2026, and pay your first premium.

These dates nearly changed. A 2025 federal rule would have ended open enrollment on December 15. A federal court vacated that part of the rule in June 2026, and CMS (Centers for Medicare & Medicaid Services) confirmed in July 2026 that the January 15 end date stands for this season. An appeal is still pending, so future years could look different.

States that run their own exchange set their own dates. Idaho closes on December 15, 2026, while California, New York, New Jersey, and Washington, D.C. run through January 31, 2027. Connecticut runs from October 23, 2026 to January 15, 2027.

Medicare Dates

The Medicare Annual Enrollment Period runs from October 15 to December 7, 2026. Changes made by December 7 take effect on January 1, 2027.

Employer Plan Dates

Employer plan dates depend on each employer’s plan year:

• Timing: usually October or November for plans that start January 1.

• Length: each employer sets its own window, and it often lasts only two to four weeks.

• Non-calendar plan years: if your company’s plan year doesn’t follow the calendar year, your window will fall at a different time.

Types of Open Enrollment

Open enrollment is the yearly window to sign up for, change, or cancel health insurance, but it works differently depending on where your coverage comes from.

ACA Marketplace Open Enrollment

Apply for 2027 coverage through Healthcare.gov from November 1, 2026 to January 15, 2027, or through your state exchange on its own dates. This window is for individuals and families who buy their own coverage, such as self-employed people and early retirees.

Medicare Open Enrollment

Medicare open enrollment runs from October 15 to December 7, 2026, and changes take effect January 1, 2027. It’s for people already on Medicare who want to switch between Original Medicare and Medicare Advantage, or change Part D drug plans. First-time Medicare sign-up happens separately, around your 65th birthday.

Employer Open Enrollment

Employer open enrollment is the window, usually in October or November, when employees choose or change workplace health, dental, vision, and other benefits for the next plan year. Your employer sets the dates and the options.

Medicare Open Enrollment: Dates, Rules, and Options

Medicare open enrollment for 2027 coverage runs from October 15 to December 7; anyone on Medicare can switch between Original Medicare and Medicare Advantage, change Advantage plans, or join, switch, or drop a Part D drug plan. Changes start January 1, 2027.

The Medicare Advantage Open Enrollment Period runs from January 1 to March 31, 2027, for people already in an Advantage plan. You get one change: another Advantage plan, or Original Medicare plus a Part D plan. It takes effect the following month.

Before the AEP opens, your plan sends an Annual Notice of Change (ANOC) listing next year’s changes to premiums, copays, networks, and covered drugs. Read it before you decide whether to stay or switch.

Initial Enrollment Period

The Initial Enrollment Period is the 7-month window around your 65th birthday: the 3 months before, your birthday month, and the 3 months after. Missing it without other qualifying coverage, such as an employer plan, can mean lifelong late enrollment penalties.

General Enrollment Period

The General Enrollment Period runs from January 1 to March 31. It’s for people who missed their Initial Enrollment Period and want to sign up for Parts A and B. Since 2023, coverage starts the month after you sign up, rather than July 1. Late penalties may still apply.

Medigap Open Enrollment

Your Medigap open enrollment period is a one-time, 6-month window that starts when you are 65 or older and enrolled in Part B. During it, insurers can’t deny you a policy or charge you more because of your health.

Dual Eligible Special Needs Plans

Dual Eligible Special Needs Plans (D-SNPs) are Medicare Advantage Plans for people who have both Medicare and Medicaid. Dual-eligible people have special enrollment options that let them make certain changes outside the AEP.

ACA Marketplace Open Enrollment: How to Enroll

To enroll in a 2027 Marketplace plan, go to HealthCare.gov between November 1, 2026 and January 15, 2027, or use your state’s own exchange and its dates.

HealthCare.gov vs State Exchanges

Both HealthCare.gov and state exchanges let individuals and families buy their own Marketplace coverage; the main difference is the calendar. Most states use HealthCare.gov and follow the federal calendar. Others run their own exchanges with their own deadlines, such as Covered California, NY State of Health, and Access Health CT. If you live in one of these states, use your state’s dates.

Who Can Buy a Marketplace Plan

To buy a Marketplace plan, you must:

• Be a US citizen, US national, or lawfully present immigrant

• Live in the state where you apply

• Not be incarcerated

• Not be enrolled in Medicare

Many buyers qualify for income-based premium tax credits. The enhanced credits available from 2021 to 2025 expired and haven’t been renewed, so the original income rules apply to 2027 plans.

What You Need to Enroll

Have Social Security numbers, income details, information on any job-based coverage offered to your household, and immigration documents, if they apply. Then:

1. Create an account on HealthCare.gov or your state exchange.

2. Complete the application, including your estimated 2027 income.

3. Compare plans by premium, deductible, network and metal tier

4. Choose a plan and enroll.

5. Pay your first premium to the insurer so your coverage can start.

Employer Open Enrollment

Employer open enrollment, sometimes called health plans open enrollment, is your yearly chance to choose or change workplace benefits. There’s no national date; your employer sets it.

When Do Employers Hold Open Enrollment

Most employers hold it in October or November for plans starting January 1, timed to their plan year. The window is usually short, and the most common employee question is simply, “When does it close?” Watch for emails from HR in early fall.

What Employees Can Change

• Switch medical plans, such as from PPO to a high-deductible plan

• Add or remove dependents

• Set HSA and FSA contributions

• Update dental, vision, and life insurance

• Waive coverage if you’re covered elsewhere

After the window closes, these choices are usually locked until next year unless you have a qualifying life event.

Auto-Renewal vs Active Enrollment

Auto-renewal, also called passive enrollment, means last year’s choices roll over if you do nothing. Active enrollment means everyone must choose again or risk losing coverage. Even with passive enrollment, health FSA elections usually don’t carry over, so doing nothing can mean no FSA next year.

Special Enrollment Periods: Enrolling Outside Open Enrollment

A Special Enrollment Period is a window outside open enrollment, opened by a qualifying life event, when you can enroll or change plans mid-year.

What is a Qualifying Life Event?

A qualifying life event is a major change that lets you enroll outside open enrollment through a Special Enrollment Period. Common examples include marriage or divorce, having or adopting a child, losing other health coverage (including job-based coverage), and moving to a new area.

How Long You Have to Enroll

How long you have depends on your type of coverage:

• Marketplace plans: usually 60 days after the event.

• Employer plans: at least 30 days after events like marriage, birth, or loss of other coverage, under federal HIPAA rules.

Expect to show proof, such as a marriage certificate or a letter confirming lost coverage.

Medicaid and CHIP: Enroll Any Time

You can apply for Medicaid and the Children’s Health Insurance Program (CHIP) any day of the year. Neither program has an open enrollment window, and eligibility depends on income and state rules.

Open Enrollment vs Special Enrollment

The main difference is timing and who qualifies: open enrollment is a fixed window each year for anyone eligible for the plan, while special enrollment starts only with a qualifying life event.

What If You Miss the Open Enrollment Deadline?

If you miss the open enrollment deadline, you generally need a qualifying life event to enroll before the next window. Still, missing it doesn’t always mean a year without coverage.

If You Missed ACA Open Enrollment

If you missed ACA open enrollment, you generally can’t enroll in a Marketplace plan until November 1 unless you qualify for a Special Enrollment Period. Your options:

• Check for a Special Enrollment Period. A move, job loss, marriage or new baby may open a 60-day window.

• Check Medicaid and CHIP. You can apply any time of the year.

• Consider short-term insurance carefully. These plans aren’t ACA-compliant and can exclude pre-existing conditions. A 2024 rule capped them at four months, but federal agencies paused enforcement of that limit in August 2025 while a new rule is written, and some states ban them.

• Wait for the next window, which opens November 1.

If You Missed Employer Open Enrollment

If you missed your employer’s open enrollment, your benefits are usually locked until next year unless you have a qualifying life event. Your options:

• Ask HR right away. They may be able to fix a missed election if the window has only just closed.

• Wait for a qualifying life event, which reopens your options for at least 30 days

• Enroll at the next open enrollment

Lesser-Known Open Enrollment Periods

Several other groups have their own windows, and these don’t always line up with Medicare or the Marketplace.

FEHB Open Season for Federal Employees

Federal Employees Health Benefits (FEHB) Open Season for the 2027 plan year runs from November 9 to December 14, 2026. Postal Service employees and annuitants now use the separate Postal Service Health Benefits (PSHB) Program which has the same dates.

TRICARE Open Season

TRICARE Open Season runs from November 9 to December 8, 2026, with changes starting January 1, 2027. Eligible military families and retirees can enroll in, or switch between, TRICARE Prime and TRICARE Select. It doesn’t apply to active-duty service members or TRICARE For Life.

Dental and Vision Open Enrollment

Dental and vision enrollment depends on where you get the coverage. Through an employer, they’re usually part of the same open enrollment. Standalone plans are often sold year-round, though waiting periods for major services are common.

Retiree Health Insurance

Retiree health insurance enrollment depends on the plan your former employer or union offers. These plans have their own enrollment windows, often timed around Medicare’s Annual Enrollment Period. Read the plan’s mailings before changing your Medicare coverage, since some changes can affect your retiree benefits.

Tips For Making the Most of your Open Enrollment

To make the most of your open enrollment, review your current coverage, estimate next year’s needs, and compare the total cost of each plan. A little prep before the window opens can save you money and stress all year.

Review Your Current Coverage

Don’t assume next year’s plan matches this year’s. Check for changes to your premium, provider network, and drug list. For Medicare, that’s your Annual Notice of Change; for Marketplace and employer plans, it’s your renewal notice.

Estimate Next Year’s Needs

Think about planned procedures, ongoing prescriptions, specialist visits, and family plans like a pregnancy. A plan that’s cheap when you’re healthy can cost more in a year with a lot of care.

Compare the Total Cost, Not Just the Premium

The premium alone doesn’t show what a plan will cost you. Add up the premium, deductible, copays, and coinsurance to see what each plan could really cost. The Summary of Benefits and Coverage (SBC), which every plan must provide, lays these out in a standard format so you can compare plans side by side.

Plan comparison tools on HealthCare.gov and Medicare.gov’s Plan Finder can also help, and Marketplace shoppers should factor in premium tax credits.

Stay Ahead of Open Enrollment Deadlines: How Keka Helps HR Teams

Open enrollment comes around every year, but each type runs on its own clock. For 2027 coverage, Medicare’s Annual Enrollment Period runs from October 15 to December 7, 2026, and HealthCare.gov open enrollment runs from November 1, 2026 to January 15, 2027, with December 15 as the deadline for a January 1 start. Most employer windows close in October or November. If you miss a deadline, check for a special enrollment period or Medicaid eligibility before you wait a full year.

For HR teams, open enrollment has two jobs: getting employees to act, and making sure their choices land correctly in payroll. That means announcing the timeline a few weeks early, explaining plan changes and the employer waiver process in plain language, tracking who has enrolled, waived, or not acted yet, and closing the window on time.

An HR platform that brings benefits enrollment, payroll deductions, and employee records together makes both jobs easier. With Keka’s US payroll and benefits, employees can compare plans and see cost previews before they enroll, and their elections sync to payroll automatically. Keka also supports Section 125, HSA, and COBRA tracking for businesses of all sizes.

Request a demo to see how it works for your team.

FAQs

What does open enrollment mean?

Open enrollment means the yearly window when you can sign up for, change, or cancel health insurance without a qualifying life event. ACA Marketplace plans, Medicare, and employer plans each have their own window. Outside it, you usually need a special enrollment period.

When is open enrollment for health insurance in 2026?

In fall 2026, Medicare open enrollment runs from October 15 to December 7, and HealthCare.gov open enrollment runs from November 1, 2026 to January 15, 2027. Both are for 2027 coverage. Most employers hold enrollment in October or November.

Is open enrollment over?

No, not yet for 2027 coverage. HealthCare.gov open enrollment runs until January 15, 2027, and Medicare’s runs until December 7, 2026. Once those windows close, you’ll need a special enrollment period, though Medicaid and CHIP accept applications all year.

Can I enroll in health insurance after January 15th?

No, not usually on HealthCare.gov, because open enrollment for 2027 coverage ends January 15, 2027. Some state exchanges, including Covered California and NY State of Health, run until January 31. After that, you need a qualifying life event or Medicaid eligibility.

What are the Medicare open enrollment dates for 2026?

The Medicare Annual Enrollment Period runs from October 15 to December 7, 2026, with changes starting January 1, 2027. The Medicare Advantage Open Enrollment Period and the General Enrollment Period both run from January 1 to March 31, 2027.

What is the difference between open enrollment and special enrollment?

The difference is timing and eligibility: open enrollment is a fixed yearly window open to everyone eligible for a plan, while a special enrollment period opens only after a qualifying life event, such as job loss, marriage, or a new baby, and usually lasts 30 to 60 days.

What counts as a qualifying life event?

A qualifying life event is a major change that lets you enroll outside open enrollment. Examples include losing other health coverage, marriage or divorce, having or adopting a child, moving to a new area, and some changes in household income.

Do I need to re-enroll every year?

No, not always. Many Marketplace and employer plans renew automatically if you do nothing. But premiums, networks, and drug lists change every year, so it’s worth reviewing your options. Health FSA elections usually must be made again each year.

When does employer open enrollment usually happen?

Most employers hold open enrollment in October or November for plans starting January 1, and the window often lasts two to four weeks. Companies with a different plan year enroll at other times, so HR shares the exact dates.