When you can go back
| Window | Dates | Original Medicare starts |
|---|---|---|
| Medicare open enrollment | October 15 to December 7 | January 1 |
| Medicare Advantage Open Enrollment Period | January 1 to March 31 | First of the month after your request |
| Special Enrollment Period (moving, plan ending, SoonerCare and others) | Depends on the reason | Depends on the reason |
The Medigap question in Oklahoma
Original Medicare pays about 80% of approved Part B costs after the deductible and has no yearly out-of-pocket limit, so many people want a Medigap policy. Whether you can get one without health questions depends on why you're leaving:
- Guaranteed issue: your plan is ending or leaving your county, you move out of its area, or you're within 12 months of trying Medicare Advantage for the first time (the trial right). Apply from 60 days before to 63 days after your plan coverage ends.
- No guaranteed issue: the company can review your health. The Oklahoma Insurance Department says its birthday rule doesn't apply to people in Medicare Advantage.
Once you're on a Medigap policy, though, Oklahoma's birthday rule lets you switch every year to equal or lesser benefits without health questions, as long as you keep coverage with no gap longer than 90 days. See switching from Medicare Advantage to Medigap.
How to go back
- Apply for Medigap first. Without a guaranteed-issue right, wait to leave your plan until a Medigap company approves you.
- Join a Part D plan. Oklahoma has 9 standalone Part D plans for 2027, available statewide. Joining one in an eligible window ends your Medicare Advantage plan.
- Line up start dates. Make Medigap and Part D start the day your Medicare Advantage coverage ends.
- Keep your Medicare card. With Original Medicare you show your red, white and blue card at the doctor.
To compare Medigap policies and Part D plans from the companies they work with, you can request a call from a licensed insurance agent. See Medicare open enrollment in Oklahoma and our Medigap vs. Medicare Advantage comparison.
Related questions
Can I switch after open enrollment?
The January to March window and more.
My plan is ending in 2027
Your guaranteed-issue right.
When is open enrollment for 2027?
October 15 to December 7, 2026.
Sources
- Medicare.gov — Understanding Medicare Advantage and Medicare Drug Plan Enrollment Periods
- Medicare.gov — When can I buy a Medigap policy? (guaranteed-issue rights)
- Oklahoma Insurance Department — New Medicare Supplement Open Enrollment FAQs
- Medicare.gov — Compare Original Medicare and Medicare Advantage
- CMS — CY2027 Landscape file
More questions in this guide
- Can I switch Medicare Advantage plans after open enrollment ends?
- My Medicare Advantage plan is ending in 2027 in Oklahoma. What do I do?
- When is Medicare open enrollment in Oklahoma for 2027?
- Which Medicare companies are leaving Oklahoma in 2027?
Part of the guide: Medicare Open Enrollment in Oklahoma (2027 Plans) · All questions
Frequently asked questions
Do I have to call my Medicare Advantage plan to leave?
Not if you join a standalone Part D plan during open enrollment or the January to March window; that ends your Medicare Advantage enrollment automatically. You can also call 1-800-MEDICARE to disenroll.
When does Original Medicare start?
If you switch during open enrollment, on January 1. If you switch between January 1 and March 31, on the first of the month after your request.
Will I pay a penalty for going back?
Not for returning to Original Medicare. But if you go 63 days or more without creditable drug coverage, you may owe a Part D late enrollment penalty, so join a drug plan at the same time.
Can I use my old Medigap policy?
If you dropped a Medigap policy to try Medicare Advantage for the first time and return within 12 months, you can buy your old policy back if the same company still sells it, or certain other plans if it doesn't.
Medicare in your Oklahoma county
Plans, local agents and help, county by county: Oklahoma · Tulsa · Cleveland · Canadian · Comanche · Rogers · Wagoner · Payne · Pottawatomie · Creek · Muskogee · Garfield · Grady · Washington · Logan · Bryan · Le Flore · Carter · Cherokee · McClain · All 77 counties →