Blog / Part D

How do I sign up for Part D for the first time?

What you need before you can enroll, the three ways to do it, and the checks worth doing first.

Updated August 17, 2026 · 2 min read

Enrolling in a drug plan takes about fifteen minutes. Choosing the right one takes about thirty. Doing them in that order saves money.

What you need first

• Enrollment in Part A or Part B. You need at least one.
• Your Medicare number and the effective dates from your red, white and blue card.
• A complete list of your medications with dosages.
• The name of the pharmacy you use.

If you do not have your Medicare card yet, that comes first. See enrolling in Medicare.

Choose the plan before you enroll

1. Go to the Plan Finder at Medicare.gov and enter your ZIP.
2. Enter every medication with exact dosage.
3. Add your pharmacy, plus mail order to compare.
4. Sort by total estimated annual cost, not premium.
5. Check the top few for prior authorization, step therapy and quantity limits.

Three ways to enroll

• Through the Plan Finder at Medicare.gov, directly into the plan you chose
• Directly with the plan, by phone or on its website
• Through a licensed agent

The premium is identical across all three. Plan premiums are filed with CMS, so using an agent costs you nothing extra. What it adds is comparison across carriers and someone to call when a drug gets denied.

When you can enroll

• Your Initial Enrollment Period, the seven months around your 65th birthday
• Annual Enrollment, October 15 to December 7, effective January 1
• Within two months of losing creditable employer drug coverage
• A special enrollment period for a move, a change in Medicaid or Extra Help, or your plan leaving the area

See all the Part D windows.

After you enroll

1. You get a confirmation. Keep it with the plan name and date.
2. Your plan card arrives before the effective date. Take it to the pharmacy along with your prescriptions.
3. If you had another drug plan, it ends automatically when the new one begins. You do not cancel it separately.
4. Fill a prescription early in the month to confirm everything is active rather than discovering a problem when you actually need it.

Check Extra Help first

If your income is limited, apply for Extra Help before you enroll. It reduces premiums, deductibles and copays substantially, waives the late enrollment penalty, and gives you more flexibility to switch plans through the year.

The limits are higher than most people assume and it is widely unclaimed here. See Extra Help.