A Simple Open Enrollment Timeline and Checklist for HR Teams

Open enrollment goes smoothly when the work starts early. This guide gives HR teams a simple timeline and checklist. It assumes a plan year that starts January 1. If your plan year starts on another date, shift the steps to match.

How to read this guide: Items marked (rule) are tied to a deadline in a government source listed below. Items without that mark are suggested timing based on common practice. Adjust them to fit your team, your insurer, and your broker.

4 to 6 months before the plan year (July to August)

• Review last year: what questions came up, what went wrong, and how many people enrolled.
• Meet with your broker or insurer about renewal pricing and plan changes.
• Look at what other employers offer. BLS and KFF publish yearly data. See Benefits that help you hire and keep good people.
• Check your headcount. Your size can change which rules apply, such as COBRA at 20+ employees and the ACA employer rules at 50+ full-time employees, including equivalents. See Benefits compliance basics.

3 to 4 months before (September)

• Decide on plan options, employee contributions, and any HSA or 401(k) employer contributions.
• If you offer an HSA-qualified plan, confirm it meets the IRS limits for the coming year. For 2027, the minimum deductible is $1,750 self-only / $3,500 family, and the out-of-pocket maximum is $8,700 / $17,400 (IRS Revenue Procedure 2026-24).
• If you are an applicable large employer, ask your broker to confirm the coverage is affordable and provides minimum value under the ACA.
• If you have a safe harbor 401(k), plan the safe harbor notice. The DOL/IRS booklet 401(k) Plans for Small Businesses says employees must get this information before the beginning of each year. (rule)
• Draft your employee communication plan. See Open enrollment communication.

By October 14

• Send the Medicare Part D creditable coverage notice if your plan includes prescription drug coverage. CMS says it must go to Medicare-eligible people before October 15 each year. (rule)

1 to 2 months before (October to November)

• Get a Summary of Benefits and Coverage (SBC) for each health plan option. It goes out with enrollment materials. If coverage renews automatically, it is due at least 30 days before the plan year starts (29 CFR 2590.715-2715). (rule)
• If you are making a change that reduces benefits, ask your adviser about notice timing. The DOL says a summary of material modifications for a material reduction in group health benefits is generally due within 60 days of adoption. (rule)
• Update payroll deductions, the enrollment system, and forms.
• Hold enrollment meetings or webinars, and give printed materials to workers who aren't at a desk.
• Explain how health FSA elections work. IRS Publication 969 says employees designate how much they want to contribute at the beginning of the plan year. Tell employees whether your plan needs a new election each year.
• Remind employees of the coming year's limits that have already been announced. For 2026, the health FSA limit was $3,400. As of Nov 2026, the 2027 limit had not been published.

Open enrollment window (often 2 to 4 weeks)

• Send reminders at the start, the middle, and 2 to 3 days before the deadline.
• Track who hasn't enrolled, and follow up.
• Answer questions quickly. Keep a running FAQ.

After enrollment closes (December)

• Send elections to insurers, HSA/FSA providers, and the 401(k) recordkeeper.
• Send confirmation statements to employees and ask them to check for errors.
• Test payroll deductions before the first payroll of the new year.

After the plan year starts (January to March)

• Check the first paychecks for deduction errors.
• Complete the online Disclosure to CMS within 60 days after the start of the plan year, if your plan has prescription drug coverage. (rule)
• HSA employer contributions are reported on Form W-2, box 12, code W (IRS Publication 969). (rule)
• If you are an applicable large employer, file Forms 1094-C and 1095-C. For calendar year 2025, the IRS instructions listed a filing deadline of March 2, 2026, or March 31, 2026 if filed electronically. Check the current instructions for this year's dates. (rule)
• Give the SPD to new participants within 90 days after they join an ERISA plan (DOL). (rule)

All year long

• New hires: give the COBRA general notice within 90 days after coverage starts (DOL). (rule)
• Life events: remind employees they generally have 30 days to ask for HIPAA special enrollment after events like marriage, birth, adoption, or losing other coverage (DOL). (rule)
• Departures: notify your COBRA administrator within 30 days of a qualifying event, such as a termination, if you use one (DOL). (rule)

A made-up example calendar

This example is made up to show the idea. Your dates will be different.