Reviewed by Russell Noga, Licensed Medicare Insurance Broker (all 50 states) — Last updated November 4, 2026
You can change Medicare Supplement plans in any month of the year, because Medigap has no annual enrollment period; the catch is that outside a protected window the new insurer can ask health questions and decline you. Protected windows include your first six months with Part B, 63-day guaranteed issue situations, the Medicare Advantage trial right and state birthday or anniversary rules.
2027 by the Numbers
63 days
window to use a federal guaranteed issue right after other coverage ends (Medicare.gov)
30 days
free look period to review a new Medigap policy while the old one stays active
16
states with a birthday rule in KFF’s count, including laws starting in 2026 and 2027
Jan. 1, 2027
start of New Mexico’s birthday rule (SB 21)
Many people assume the fall Medicare enrollment season is when supplements change. It isn’t. The October 15 to December 7 period covers Medicare Advantage and Part D, not Medigap. A supplement switch can happen in March or July just as easily, and the timing that matters is tied to your own dates: when Part B began, when other coverage ended, or when your birthday falls in certain states.
This page sorts every route into a single timing map, then shows the order of steps that keeps you from paying twice or ending up uncovered. For the basics of the first window, see our Medigap open enrollment period guide.
✔ Based on CMS 2027 data
✔ Free plan comparison
