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Ask an Aging Expert: Why can't I Enroll in Medicare all year?

Initial Enrollment, General Enrollment, Special Enrollment, Annual Enrollment, Medicare Advantage Open Enrollment, Five Star Enrollment. When it comes to Medicare, there are enrollment periods for everything. Different enrollment periods have different rules and apply to different people. Understanding the different enrollment periods is vital to make sure you don’t end up paying too much for your Medicare costs.

Before we talk about the different enrollment periods, it is important to discuss why Medicare uses enrollment periods at all. Because of the laws related to Medicare enrollment, most people become eligible for Medicare in the month they turn 65 years old. The law specified that

people would have a 7-month window around their birthday to enroll in coverage. It also specified that people who chose not to take Medicare in this Initial Enrollment Period would be subject to penalties if they wanted to join Part B later. The law also established a window of time each year when people who did not enroll in their Initial Enrollment Period could enroll in Part B. So, the short answer as to why you can’t enroll in Medicare all year long is that the legislation that created Medicare also limited when people could enroll. An act of congress is required to make changes to Medicare Enrollment periods.

Now that we have discussed why enrollment periods exist, let’s break down all the enrollment periods.

Initial Enrollment Period

The Initial Enrollment Period is the three months before, the month of and the three months after a person’s 65th birthday or surrounding the 25th month of disability. This is the first opportunity someone has to enroll in Medicare and applies to Medicare Part A, Part B, Part D and Medicare Advantage Plans. If you are already collecting Social Security benefits during the Initial Enrollment Period, you are automatically enrolled in Part A and B. You can waive enrollment if you are automatically enrolled. If someone qualifies for Medicare before their 65th birthday due to a disability, they receive another Initial Enrollment Period at their 65th birthday. When you enroll during an Initial Enrollment Period there are no late enrollment penalties.

General Enrollment Period

If you do not enroll in Medicare during the Initial Enrollment Period and have no other qualifying coverage, you can only enroll in Part B of Medicare during General Enrollment. General Enrollment is from January 1st to March 31st each year. People who enroll in Part B during the General Enrollment Period will have a late enrollment penalty for the time they were without coverage.

Medicare Supplement Open Enrollment Period

Starting the day your Part B becomes effective, the Medicare Supplement Open Enrollment Period lasts 6 months. During this period, you can purchase a Medicare Supplement plan without the risk of being denied. After this enrollment period, you can still purchase Medicare Supplement plans if the plan accepts you, but you can be denied coverage due to pre-existing conditions.

Annual Enrollment Period

The Annual Enrollment Period, also called the Open Enrollment Period is from October 15th to December 7th each year. During this enrollment period, you can make changes to your coverage for the next year. You can switch from Original Medicare to a Medicare Advantage Plan or from an Advantage Plan back to Original Medicare. You can also move from one Medicare Advantage Plan to another. In addition, you can enroll in, change or drop your Medicare Part D plan. Keep in mind, if you enroll in a Part D plan for the first time during the Annual Enrollment Period, you will have a penalty for all the time you were without qualifying drug coverage.

Medicare Advantage Open Enrollment Period

A relatively new enrollment period, the Medicare Advantage Open Enrollment Period allows anyone enrolled in a Medicare Advantage Plan to make a one-time change in their coverage between January 1 and March 31. This is especially helpful for people who decided to try a new Medicare Advantage plan and are unhappy with the coverage. They can use this enrollment period to enroll in a new Medicare Advantage plan or return to Original Medicare. Keep in mind, someone on Original Medicare cannot enroll in a Medicare Advantage Plan during this enrollment period.

Five Star Enrollment Period

Medicare uses a star rating to signify performance for Part D and Medicare Advantage plans. The highest rating for a plan is five stars. To incentivize plans to perform to a high standard, Medicare instituted the Five Star Enrollment Period. If there are plans in your area that have achieved the five-star rating, you can enroll in those plans outside normal enrollment periods. This enrollment period is effective all year except for the first week of December.

Special Enrollment Periods

There are a wide variety of other circumstances that allow for enrollment outside the normal enrollment periods. These are referred to as Special Enrollment Periods. The most common circumstance is losing employer-based coverage. You have 8 months from the end of that coverage to enroll in Medicare. As long as you enroll during that window, you will not have a late enrollment penalty.

Part D and Medicare Advantage Plans also have a variety of special circumstances that allow you to enroll in or change plans outside normal enrollment periods. If you have moved, lost coverage from a plan, qualify for assistance programs or were impacted by disasters, you may qualify for a Special Enrollment Period. For a full list of special enrollment periods, visit

The Medicare Annual Enrollment Period is just around the corner. If you would like to review your coverage for the upcoming year, the SHIP program is here to help! SHIP counselors are highly trained and unbiased. Reviewing your coverage with a SHIP counselors can save hundreds of dollars every year. To set an appointment with a SHIP counselor with the Area Agency on Aging- Five County, call (435)673-3548.

Amy Brinkerhoff has worked for the Five County Association of Governments for over ten years. She graduated from Brigham Young University with a degree in Sociology. Amy has been a SHIP counselor since her first week at Five County and now serves as Coordinator for the SHIP and SMP programs, where she offers one-on-one Medicare Counseling and teaches classes on Medicare topics and Fraud prevention.

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Patriot IB
Patriot IB
May 02, 2023

You can also choose to switch your Medicare Part D prescription drug coverage plan. This is the only time during the year you are eligible to make changes to your Original Medicare plan unless you qualify for a special enrollment period.

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