Medicare Part B Special Enrollment Period in Hawaii — the 8-month window after retirement
If you delayed Medicare Part B because you had employer coverage past 65, you have a Special Enrollment Period (SEP) when that coverage ends. Get the timing and paperwork right and you avoid lifetime late enrollment penalties. Get it wrong and you can owe 10% extra on every Part B premium for as long as you have Medicare.
When the Part B SEP starts and how long it lasts
Your Part B Special Enrollment Period starts the month after either:
- Active employment ends (yours or your spouse's), OR
- Active-employment-based group health coverage ends
...whichever comes first. The SEP lasts 8 months from that trigger.
Critical timing: The 8 months is calendar months, not 8 monthly statements. If active employment ends June 15, your SEP runs July 1 through February 28 of the following year. Don't wait until month 7 — your coverage doesn't start until the month after you enroll, so a late enrollment can leave you uninsured for several weeks.
The COBRA trap — why COBRA doesn't extend your SEP
This is the single most expensive Medicare timing mistake people make:
COBRA does not extend your Part B Special Enrollment Period. Your SEP starts when active employment ends, not when COBRA ends. If you retire and elect COBRA at 65 thinking "I'll switch to Medicare when COBRA runs out 18 months later," you'll likely face:
- A late enrollment penalty (10% per 12-month period you went without Part B)
- A wait until the next General Enrollment Period (January 1 – March 31) to actually enroll
- Coverage that doesn't start until the month after you enroll (potentially July 1 if you enroll in March)
The right move when employer coverage ends at 65+: enroll in Medicare Part B during the 8-month SEP, regardless of whether you elect COBRA. COBRA can be a useful supplement during the transition month if you have ongoing care, but don't let it delay your Part B enrollment.
The Form CMS-L564 — what HR needs to fill out
To enroll in Part B during the SEP without penalty, you need to prove you had employer coverage through current employment. Social Security uses two forms:
Form CMS-40B — Application for Enrollment in Part B
This is your Part B enrollment application. You complete it yourself and submit to Social Security.
Form CMS-L564 — Request for Employment Information
This proves you had active employer coverage. Your HR department or employer must complete the bottom of this form. They'll certify:
- Dates of employment
- Dates of group health coverage
- Whether the coverage was based on current or former employment
Get Form CMS-L564 signed by HR while you still have access to them — ideally in your last few weeks of employment. Tracking down a former employer years later is a common cause of stuck applications.
How to submit your Part B SEP application
Three submission options:
- Online at SSA.gov — fastest. Upload both completed forms.
- By fax to your local Social Security office
- In person at a Social Security office (Hawaii has offices in Honolulu, Hilo, Kona, Kahului, and Lihue — see our phone numbers and offices guide)
Allow at least 30-45 days for processing. Coverage starts the month after Social Security approves the application — there's no retroactive option.
The Part B late enrollment penalty
If you miss the SEP and don't have other qualifying coverage, the penalty is steep:
| Months without Part B (after eligible) | Penalty | 2026 monthly cost (on standard $202.90 premium) |
|---|---|---|
| 0–11 months | 0% | $202.90 |
| 12–23 months | 10% | $223.19 |
| 24–35 months | 20% | $243.48 |
| 36–47 months | 30% | $263.77 |
| 48–59 months | 40% | $284.06 |
The penalty is calculated on the standard premium and applies for as long as you have Medicare — typically 20+ years. A 30% penalty over 25 years adds up to roughly $18,000+ in extra premiums.
If you missed the SEP — General Enrollment Period
If you missed your SEP, your only options are:
- General Enrollment Period (GEP) — January 1 through March 31 each year. Coverage starts the month after you enroll. The late enrollment penalty applies.
- Equitable Relief — Social Security can waive the penalty if you can prove you were misled by a federal employee or representative. Hard to qualify for. Sage PLUS Hawaii can help you build a request.
Don't forget Part D — separate enrollment
The Part B SEP doesn't automatically enroll you in Part D. If your employer drug coverage was creditable, you also have a separate Part D Special Enrollment Period — typically 2 months after creditable coverage ends. Miss this and you face the Part D late enrollment penalty (1% of the national base beneficiary premium per month). See our Part D creditable coverage guide.
Medigap timing — limited Hawaii implications
Your Medigap Open Enrollment Period is 6 months from the date you enroll in Part B (not from age 65 if you delayed). During this window, Medigap insurers cannot deny you coverage or charge more for pre-existing conditions. Outside this window in Hawaii, Medigap underwriting applies — insurers can refuse you.
This is a major reason not to delay Part B enrollment longer than necessary: every month of delayed Part B is a month of delayed Medigap guaranteed-issue rights.
Hawaii-specific SEP situations
EUTF state retirees
If you're retiring from a state, county, or DOE job in Hawaii, EUTF coordinates closely with Medicare. EUTF retiree coverage typically requires Medicare Part B enrollment — your EUTF retiree premium and reimbursement assume you have Part B. See our EUTF guide.
Federal employees and PSHB
Federal civilian employees retiring under FEHB have specific rules. Postal retirees moved into PSHB in 2025 — most must enroll in Part B at 65 to keep PSHB coverage. See FEHB/PSHB and Medicare.
Inter-island move during SEP
If you move to a different island during your 8-month SEP, your SEP doesn't reset, but your Medicare Advantage plan options will change. You also get a separate SEP for moving permanently to a new service area (60 days before through 2 months after the move) for MA and Part D plan changes.
Working past 65 in Hawaii's small businesses
Most Hawaii businesses have fewer than 20 employees, meaning Medicare was primary the whole time you were working — you should have been on Medicare. If you weren't, you may face a late enrollment penalty for the entire period you went without Part B, even though you had employer coverage. Talk to a licensed agent or Sage PLUS to assess your situation.
Action checklist for Hawaii kupuna planning to retire
- Identify your retirement date. Your SEP starts the month after that date (or when employer coverage ends, whichever is first).
- Get Form CMS-L564 signed by HR before you leave. Don't wait until you need it.
- Apply for Part B enrollment at SSA.gov as soon as you have the date confirmed — you can apply up to 3 months before coverage starts.
- Don't rely on COBRA as a substitute for Part B enrollment. The SEP runs from active employment ending, not COBRA ending.
- Plan your Part D enrollment separately — same timing principles apply.
- Use your Medigap Open Enrollment wisely — 6 months of guaranteed-issue from your Part B effective date.
- Consider Sage PLUS or a licensed agent for the transition. Find a Hawaii Medicare agent.
Frequently asked questions
8 months. The clock starts the month after either active employment ends or active-employment-based group health coverage ends, whichever comes first. So if you retire June 15, your SEP runs July 1 through February 28 of the following year.
No. This is one of the most expensive Medicare timing mistakes. The SEP starts when active employment ends, not when COBRA ends. If you wait for COBRA to expire 18 months after retirement to enroll in Part B, you'll likely face a 10% late enrollment penalty for the rest of your life.
It's the 'Request for Employment Information' form that proves you had active employer coverage and qualify for the Part B Special Enrollment Period. You start the form, and your HR department or former employer completes the bottom section certifying employment dates and coverage. Get this signed before leaving employment if possible.
Yes. The fastest path is to apply at SSA.gov by uploading completed Form CMS-40B (your application) and Form CMS-L564 (employer-completed verification). Allow 30-45 days for processing. Coverage starts the month after approval.
10% of the standard Part B premium for each full 12-month period you were eligible for Part B but didn't enroll. The penalty is permanent — added to your premium for as long as you have Medicare. On the 2026 standard premium of $202.90/month, a 30% penalty adds about $61/month, or $730/year, every year for the rest of your life.
Your next opportunity is the General Enrollment Period: January 1 through March 31 each year, with coverage starting the month after enrollment. The late enrollment penalty applies. In limited cases, you may qualify for 'equitable relief' if you can prove a federal employee or representative misled you — Sage PLUS Hawaii at 1-888-875-9229 can help build that request.
No, they're separate. Part D has its own Special Enrollment Period — typically 2 months after creditable employer drug coverage ends. Many people miss this because they're focused on Part B. See our Part D creditable coverage guide.