Missing a Medicare enrollment window can mean gaps in coverage or lifelong penalties. Here is a plain-English calendar of every enrollment period that matters in 2026.
Annual Enrollment Period (October 15 – December 7)
During AEP you can join, switch, or drop Medicare Advantage and Part D drug plans. Changes take effect January 1. This is the single most important window for most beneficiaries – plans change their costs and benefits every year, so an annual review pays off.
Medicare Advantage Open Enrollment (January 1 – March 31)
Already in a Medicare Advantage plan? You get one switch to a different Advantage plan or back to Original Medicare, with the option to add a Part D plan.
Initial Enrollment Period
Turning 65? Your 7-month window begins 3 months before your birthday month and ends 3 months after. Enrolling on time avoids late penalties on Part B and Part D.
Special Enrollment Periods
Life events – moving, losing employer coverage, qualifying for Extra Help – can open a Special Enrollment Period so you can make changes outside the standard windows.
Get Ready Before the Window Opens
Gather your medication list, preferred pharmacies, and doctors. Then compare plans or let a licensed agent do the legwork for you – it costs nothing and can save you hundreds.
Frequently Asked Questions
What happens if I do nothing during AEP?
Your current plan generally renews automatically, but its premiums, copays, and drug formulary may change for the new year.
Can I change Medigap plans during AEP?
Medigap is not tied to AEP. You can apply to change Medigap plans any time, but outside protected windows you may face medical underwriting.
Mike Sullivan
With over 20 years of experience, Mike has helped thousands of individuals and families find the right coverage and make confident healthcare decisions.
