When is Medicare open enrollment for 2027 in Colorado?

This is the Annual Enrollment Period for Medicare Advantage and Part D drug plans. In Adams County, home to Brighton, you can choose among 36 Medicare Advantage plans from 10 carriers for 2027, not counting Special Needs Plans, down from 43 plans in 2026.

Medicare enrollment windows around the 2027 plan year

Window	Dates	What you can do
Annual Enrollment Period	Oct 15 to Dec 7, 2026	Join, switch or drop Medicare Advantage or Part D for January 1, 2027
Medicare Advantage Open Enrollment	Jan 1 to Mar 31, 2027	One change if you are already in a Medicare Advantage plan
Initial Enrollment Period	7 months around your 65th birthday month	First enrollment in Parts A, B, C and D
Medigap Open Enrollment	6 months from the month you are 65 and have Part B	Buy any Medigap plan sold in Colorado without health questions
Special Enrollment Periods	Varies	After a move, loss of other coverage, a plan non-renewal and other events

How the fall window works

Between October 15 and December 7 you can move from Original Medicare to a Medicare Advantage plan, from one Advantage plan to another, back to Original Medicare, or change your stand-alone Part D plan. The last choice you make in the window is the one that counts.

Medigap (Medicare Supplement) is not tied to this window. In Colorado, buying or switching a Medigap policy outside your first 6-month window usually means answering health questions.

What changes on January 1

Your plan mailed an Annual Notice of Change by September 30 listing its 2027 premium, deductible, out-of-pocket maximum, drug list and network. In Adams County the average in-network out-of-pocket maximum rose from $5,518 in 2026 to $6,142 for 2027, and 21 of the 32 plans offered in both years raised it. Doing nothing keeps you in your plan with those new terms.

The yearly cap on Part D drug costs also moves, from $2,100 in 2026 to $2,400 in 2027.

What Adams County shoppers will notice this fall

Not every 2026 plan returns. In the CMS crosswalk, 12 Adams County plans, Special Needs Plans included, end as terminated or non-renewed contracts for 2027, and Clear Spring Health leaves the county entirely. Members of those plans get a letter and a Special Enrollment Period, but the fall window is still the simplest moment to pick a replacement.

Stand-alone drug plans thinned too. Colorado has 8 stand-alone Part D plans for 2027, down from 10 in 2026, and none has a $0 premium; monthly premiums run from $5.30 to $260.20. If you pair Original Medicare with a drug plan, weigh that premium against the drug costs it covers, never on its own.

Brighton alone has 4,228 residents aged 65 or older, according to Census estimates for 2020 to 2024, so local review appointments fill up as December 7 approaches.

What to do before December 7

List your doctors, your prescriptions and your preferred pharmacy, then compare your current plan with the alternatives for your ZIP code. Lisa offers no-cost Medicare reviews at the Brighton office, by phone or virtually. Medicare.gov and 1-800-MEDICARE list every plan available in your area.

Related questions

Sources

1. Medicare & You 2027 handbook Centers for Medicare & Medicaid Services
2. CMS Medicare Advantage and Part D Landscape, Contract Year 2027 Centers for Medicare & Medicaid Services
3. CMS 2027 Part C and D Plan Crosswalk Centers for Medicare & Medicaid Services
4. U.S. Census Bureau, American Community Survey 2020 to 2024 5-year estimates U.S. Census Bureau

Please note: We do not offer every plan available in your area. Currently we represent 10 organizations which offer 106 products in your area. Please contact Medicare.gov or 1-800-MEDICARE to get information on all of your options.Headwaters Health and Wealth is not connected with or endorsed by the United States government or the federal Medicare program. Medicare has neither endorsed nor reviewed this information.