Key dates for 2027 coverage
| Period | Dates | What you can do |
|---|---|---|
| Medicare open enrollment | October 15 to December 7, 2026 | Join, switch or drop a Medicare Advantage or Part D plan; return to Original Medicare. Changes start January 1, 2027. |
| Medicare Advantage Open Enrollment Period | January 1 to March 31, 2027 | If you're in Medicare Advantage: switch once to another Medicare Advantage plan, or go to Original Medicare and join a Part D plan. |
| Plan non-renewal Special Enrollment Period | December 8, 2026 to February 28, 2027 | If your plan isn't renewing: choose new coverage. Choose by December 31 to avoid a gap. |
| Oklahoma Medigap birthday rule | 60 days starting on your birthday, every year | Switch Medigap to equal or lesser benefits without health questions. |
What's different in Oklahoma this year
For 2027, CMS lists 50 Medicare Advantage plans open to everyone and 9 standalone Part D plans in Oklahoma. Some plans are leaving counties, and seven counties, Beaver, Cimarron, Ellis, Harmon, Harper, Roger Mills and Texas, have no Medicare Advantage plan open to everyone. If you live there and have a plan, read your mail closely. See plans ending in 2027.
Your open enrollment checklist
- Read your Annual Notice of Change. Plans mail it by September 30. It lists next year's changes to costs, networks and drug lists.
- Check your doctors and medicines. Confirm they're still covered in 2027.
- Compare plans in your county. See plans for your ZIP code or use Medicare Plan Finder.
- Decide by December 7, 2026. Enroll with the plan, through Medicare.gov, by calling 1-800-MEDICARE, or with a licensed insurance agent.
Medicare won't call you to sell a plan. Be careful with unexpected calls asking for your Medicare number. You can report suspected fraud to 1-800-MEDICARE. See Medicare fraud in Oklahoma.
To compare plans from the companies they work with, you can request a call from a licensed insurance agent. More in Medicare open enrollment in Oklahoma.
Related questions
Can I switch after open enrollment?
The January to March window and more.
My plan is ending in 2027
Deadlines and steps.
Can I go back to Original Medicare?
What to know first.
Sources
- Medicare.gov — Understanding Medicare Advantage and Medicare Drug Plan Enrollment Periods
- eCFR — 42 CFR 422.62, Election of coverage under an MA plan
- Medicare.gov — Special Enrollment Periods
- Medicare.gov — Understanding Medicare Advantage Plans (Annual Notice of Change)
- CMS — CY2027 Landscape file
- Oklahoma Insurance Department — Bulletin No. 10-2023 (Revised), birthday rule
More questions in this guide
- Can I go back to Original Medicare from Medicare Advantage?
- Can I switch Medicare Advantage plans after open enrollment ends?
- My Medicare Advantage plan is ending in 2027 in Oklahoma. What do I do?
- Which Medicare companies are leaving Oklahoma in 2027?
Part of the guide: Medicare Open Enrollment in Oklahoma (2027 Plans) · All questions
Frequently asked questions
Is the date different in Oklahoma?
No. Medicare open enrollment is set by federal rules (42 CFR 422.62) and is the same in every state. What differs is which plans are offered in your county.
What if I miss December 7?
Your current coverage continues into 2027 if your plan is renewing. If you're in Medicare Advantage, you can make one change from January 1 to March 31. Other changes need a Special Enrollment Period, such as moving or your plan ending.
Does open enrollment apply to Medigap?
No. Medigap has its own rules. In Oklahoma, if you already have a Medigap policy, the birthday rule gives you 60 days each year, starting on your birthday, to switch to equal or lesser benefits without health questions.
If I make more than one change during open enrollment, which counts?
The last choice you make by December 7 is the one that takes effect on January 1, 2027.
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 →