As you approach retirement, you'll need to think about what you're going to do for health insurance.

Most working people get their health insurance through their employer. Once you hit 65, though, you can select your medical coverage through Medicare.

It's important to understand how Medicare open enrollment works, especially because there are different rules depending on what you want to do. Here's what you need to know about the process.

What Does Open Enrollment Mean?

Medicare's open enrollment period is when people with Medicare plans can make changes to make sure their health care needs are met.

Most Americans are eligible to enroll in Medicare when they turn 65. But you can only enroll in a plan during your initial enrollment period. If you're eligible for Medicare when you're 65, your initial enrollment period is the seven-month window that opens three months before you turn 65 and closes three months after you turn 65. (If you're already receiving Social Security when you turn 65, you're automatically enrolled in Medicare.)

If you qualify but don't enroll during the initial enrollment period, you can enroll in Medicare later, but you might have to pay additional premiums.

Once you've enrolled, you can join, switch or drop a Medicare health plan or a Medicare Advantage (Part C) plan during a specific window — the open enrollment period.

How Does Open Enrollment Work?

Your health needs likely won't stay the same every year. And when they change, and you might need to make changes to your Medicare Advantage plan or Medicare drug coverage (Part D).

You can make those changes during Medicare's open enrollment periods. But the windows are only open during specific times of the year.

There are two separate enrollment periods each year.

The first, the Medicare open enrollment period, runs October 15 through December 7. During this open enrollment period, you can:

• Switch from a Medicare Advantage (Part C) plan to an Original Medicare plan.
• Switch from an Original Medicare plan to a Medicare Advantage plan.
• Switch Medicare Advantage plans.
• Enroll in, drop or switch a Medicare drug plan.

The second, the Medicare Advantage open enrollment period, is open from January 1 through March 31. If you have a Medicare Advantage plan, during this open enrollment period, you can:

• Switch to another Medicare Advantage plan.
• Unenroll in a Medicare Advantage plan and return to Original Medicare.
• Pick or switch Medicare drug coverage. (But you can't join or switch a Medicare drug plan if you're in Original Medicare during this open enrollment period.)

There is no open enrollment period for Medicare Supplement insurance plans, also called Medigap plans. Typically, the only time you can enroll in Medigap coverage is during a six-month window after you sign up for Medicare Part B.

If you switch from Medicare Advantage to Original Medicare and want a Medigap plan, you might not qualify for it. And if you do get one, you might pay more for it.

Medicare Open Enrollment FAQs

Here are a few common questions about Medicare open enrollment.

• Do I have to make any changes? No. If you're happy with your current coverage, you can keep your plan. Generally, your coverage will automatically renew on January 1.
• Can I change my insurer? Yes. If you have a Medicare Advantage plan, you can change your insurers if you switch plans during the open enrollment period.
• How can I compare Medicare Advantage plans if I'm interested in switching? Use the Medicare plan finder. Create an account, and you'll be able to compare the available Medicare Advantage plans in your area.
• Can I change my plan outside those enrollment windows? Generally, no. However, there are specific circumstances that qualify you for Medicare's special enrollment period. Among those circumstances:
  • You've moved.
  • You've lost your current coverage (for example, you're no longer eligible for Medicaid, or if you've left your employer or union).
  • Your plan has changed its contract with Medicare.

Even if you're currently happy with your coverage, it never hurts to look at your options during the Medicare open enrollment period. The most important thing is getting the best coverage that fits your needs and your budget.