Four plan types, and which ones go together
A four-column comparison of the ACA Marketplace (Covered California in this state), Medicare Advantage, Medicare Supplement and Medicare Part D. A band across the top separates the Marketplace column, for people not on Medicare, from the other three, for people on Medicare or turning 65. Rows compare who each plan type is for, what it covers, and when you can enroll: the Marketplace from November 1 to January 31 or 60 days after a life event; Medicare Advantage and Part D from October 15 to December 7, with January 1 to March 31 to switch if you are already in an Advantage plan; and a Medicare Supplement, best bought in the six-month window that starts when you have Part B at 65. The bottom row shows the two Medicare paths: Medicare Advantage on its own, or Original Medicare with a Supplement and a Part D plan together. You pick one path, not both: a Medigap policy cannot be used with a Medicare Advantage plan. Footnotes: in California, Covered California and Medi-Cal use the same application; when you first become eligible for Medicare you get your own enrollment window as well; premiums, networks and drug lists differ by plan, county and year, so this compares plan types, not plans.
Four plan types, and which ones go together
Sources: medicare.gov enrollment rules; Covered California dates
Not on Medicare
On Medicare, or turning 65
ACA
Marketplace
Covered California
Medicare
Advantage
Part C
Medicare
Supplement
Medigap
Medicare
Part D
Drug plan
Who it's for
Self-employed,
between jobs, or
buying their own
On Medicare and
comfortable with a
network
On Medicare,
any doctor who
takes Medicare
Anyone on Original
Medicare
What it covers
A whole private
plan: doctors,
hospital, drugs
Part A and Part B
in one plan, drugs
usually in it
The gaps Original
Medicare leaves
you to pay
Prescriptions
only, from that
plan's drug list
When to enroll
Nov 1 – Jan 31, or
60 days after a
life event
Oct 15 – Dec 7.
Jan 1 – Mar 31 if
already in one
Best window: 6
months from Part B
at 65
Oct 15 – Dec 7,
every year
Which pair up
On its own. Not a
Medicare plan.
One path
Advantage alone
The other path
Original Medicare + Supplement + Part D
You pick one path, not both: a Medigap policy cannot be used with a Medicare Advantage plan.
In California, Covered California and Medi-Cal use the same application.
When you first become eligible for Medicare you get your own enrollment window as well.
Premiums, networks and drug lists differ by plan, county and year. This compares plan types, not plans.
Four plan types, and which ones go together
A stacked comparison, one card per plan type, of the ACA Marketplace (Covered California in this state), Medicare Advantage, Medicare Supplement and Medicare Part D. A band above the first card separates the Marketplace, for people not on Medicare, from the other three cards, for people on Medicare or turning 65. Each card gives who that plan type is for, what it covers, and when you can enroll: the Marketplace from November 1 to January 31 or 60 days after a life event; Medicare Advantage and Part D from October 15 to December 7, with January 1 to March 31 to switch if you are already in an Advantage plan; and a Medicare Supplement, best bought in the six-month window that starts when you have Part B at 65. A block below the four cards shows the two Medicare paths: Medicare Advantage on its own, or Original Medicare with a Supplement and a Part D plan together. You pick one path, not both: a Medigap policy cannot be used with a Medicare Advantage plan. Footnotes: in California, Covered California and Medi-Cal use the same application; when you first become eligible for Medicare you get your own enrollment window as well; premiums, networks and drug lists differ by plan, county and year, so this compares plan types, not plans.
Four plan types, and which ones go
together
Sources: medicare.gov enrollment rules;
Covered California dates
Not on Medicare
ACA Marketplace
Covered California
Who it's for
Self-employed, between jobs, or buying
their own
What it covers
A whole private plan: doctors, hospital,
drugs
When to enroll
Nov 1 – Jan 31, or 60 days after a life
event
Which pair up
On its own. Not a Medicare plan.
On Medicare, or turning 65
Medicare Advantage
Part C
Who it's for
On Medicare and comfortable with a
network
What it covers
Part A and Part B in one plan, drugs
usually in it
When to enroll
Oct 15 – Dec 7. Jan 1 – Mar 31 if already
in one
Which pair up
One path: Advantage alone
Medicare Supplement
Medigap
Who it's for
On Medicare, any doctor who takes Medicare
What it covers
The gaps Original Medicare leaves you to
pay
When to enroll
Best window: 6 months from Part B at 65
Which pair up
The other path: Original Medicare +
Supplement + Part D
Medicare Part D
Drug plan
Who it's for
Anyone on Original Medicare
What it covers
Prescriptions only, from that plan's drug
list
When to enroll
Oct 15 – Dec 7, every year
Which pair up
The other path: Original Medicare +
Supplement + Part D
One path
Advantage alone
The other path
Original Medicare + Supplement + Part D
You pick one path, not both: a Medigap
policy cannot be used with a Medicare
Advantage plan.
In California, Covered California and
Medi-Cal use the same application.
When you first become eligible for Medicare
you get your own enrollment window as well.
Premiums, networks and drug lists differ by
plan, county and year. This compares plan
types, not plans.
Sources: medicare.gov enrollment rules and Covered California dates, checked September 2026.
