TL;DR: If your employer uses Sun Life to manage leave, your FMLA claim gets processed by Sun Life's absence management team, not directly by HR. You file by phone or through the Sun Life member portal, your doctor completes a medical certification, and Sun Life decides whether the leave qualifies. But Sun Life doesn't write FMLA law, the 12-week entitlement, eligibility rules, and job protections come from federal law, and Sun Life has to follow them. Here's exactly how the process works.
If your paycheck comes from one company but your leave paperwork routes to Sun Life, you're not imagining things. Large employers increasingly outsource FMLA administration to insurers and third-party administrators, and Sun Life is one of the bigger names in that business. That can be confusing, you're used to HR handling everything, and suddenly a phone call to an outside company decides whether your job is protected.
This guide breaks down what Sun Life actually does when it handles your FMLA leave, how to file a claim, what happens after you submit your paperwork, and (critically) which parts of the process are fixed by federal law no matter what Sun Life's portal or call center tells you.
What Is Sun Life's Role in Your FMLA Leave?
Sun Life is an insurance and financial services company. For FMLA purposes, what matters is its Absence Management Solutions business, the division employers hire to receive leave requests, collect medical certification, and decide whether an absence qualifies as FMLA. Sun Life describes this service on its own site as helping members "submit claims online, view real-time claims status and decisions, and upload claims documents" for absence, disability, and related benefits (Sun Life, employee benefits support).
Behind the scenes, Sun Life's absence management offering has operated through FMLASource, Inc., a company affiliated with ComPsych Corporation that handles the day-to-day leave administration on Sun Life's behalf. According to Sun Life's own materials, this bundled service is available in every state for employers with 200 or more employees; employers with 200 to 499 employees must pair it with a Sun Life insurance policy to use it (Sun Life Absence Management Solutions). In practice, this means the company reviewing your paperwork may be branded "Sun Life," but the underlying claims platform could be run by FMLASource. Don't be surprised if you see either name on your documents, they refer to the same process.
One thing worth being direct about: Sun Life is a claims administrator, not the source of your FMLA rights. It reviews the medical evidence and decides whether your specific absence meets the legal definition of a "serious health condition" or other qualifying reason. It does not have authority to shrink your 12-week federal entitlement, change the eligibility test, or override the Department of Labor's rules, more on that below.
How to File an FMLA Claim Through Sun Life
Step 1: Tell your employer first
Notify your manager or HR that you need leave. Most employers using Sun Life require this as a first step so HR can flag your leave request and point you to the right claim number. Sun Life issues employers their own dedicated intake line, so the number that works for a coworker at a different company may not work for you.
Step 2: Contact Sun Life to open the claim
You can generally reach Sun Life two ways:
Online: Create or log into a member account at sunlife.com to submit a claim and track its status.
By phone: Sun Life's general Member Services line is 1-800-247-6875, available Monday through Friday, 8 a.m. To 8 p.m. ET, according to Sun Life's own member portal. Many employers are also assigned a dedicated absence-claim intake number in their plan materials, for example, plan documents from at least one employer instruct staff to call in an FMLA/short-term disability claim at a separate number. If you don't know your employer's specific line, your HR or benefits team can give it to you, or you can start with the general Member Services number above.
Step 3: Complete the medical certification
Sun Life will send you (or your employer will provide) a Medical Certification form, which your health care provider fills out and returns. Under federal FMLA regulations, you generally must be given at least 15 calendar days to return a completed certification (29 CFR § 825.305), and Sun Life's own plan materials reference this same 15-day window. Send the form directly to Sun Life (not to your manager) since your manager typically has no role in the medical review.
Step 4: Wait for a determination
Sun Life reviews the certification and issues a decision. In plan documents we reviewed, Sun Life said it aims to send a decision packet within 48 hours of receiving a complete, provider-certified medical form; if documentation is incomplete or late, Sun Life sends reminders and processes the claim once it arrives, which can delay or affect the outcome depending on your employer's late-paperwork policy. Treat any specific turnaround time as an example from one plan rather than a guarantee, ask your own HR team or Sun Life what your plan's standard is.
Step 5: Manage your leave and your return
Once approved, you can typically check your claim status online, report changes to your leave dates, and communicate with Sun Life about extensions. Plan materials commonly require a fitness-for-duty certification from your provider before you're cleared to return, and some employer plans require you to notify your manager a few business days before an early return. These operational details vary by employer, so check your own leave packet for the exact requirements that apply to you.
Sun Life FMLA vs. Short-Term Disability (STD)
Many employers that use Sun Life for FMLA also use Sun Life to administer short-term disability. The two are separate claims that serve different purposes:
Feature | FMLA (through Sun Life) | Short-Term Disability (through Sun Life) |
|---|
What it provides | Job protection | Partial wage replacement |
Paid? | No. FMLA itself pays nothing | Often yes, per your employer's plan |
Who sets the terms | Federal law | Your employer's disability plan design |
Typical duration | Up to 12 weeks (26 for military caregiver leave) | Varies, often several weeks to 26 weeks, plan-dependent |
File both claims if you're taking medical leave for your own serious health condition. They run concurrently, not back to back, the weeks you spend on STD count against your FMLA entitlement at the same time, not in addition to it. Exactly how much of your pay STD replaces, and for how long, is set by your employer's plan, not by Sun Life or by FMLA. For instance, one employer's published plan documents show a 7-calendar-day waiting period followed by full pay through week 8 and 60% pay from week 9 through week 26, but that schedule belongs to that specific employer's plan, not to Sun Life generally, and your plan's numbers may look nothing like it. Ask your HR or benefits team for your plan's actual wage-replacement schedule, or see our guide on how FMLA and short-term disability work together for the general mechanics.
What Sun Life Can't Change About Your FMLA Rights
Sun Life administers the paperwork, but the underlying law is federal and doesn't bend to any one company's process. Under the Family and Medical Leave Act:
Eligible employees get up to 12 weeks of job-protected leave in a 12-month period, or up to 26 weeks to care for a covered servicemember.
To qualify, you generally need 12 months of employment, at least 1,250 hours worked in the past 12 months, and an employer with 50 or more employees within 75 miles.
FMLA leave is unpaid by default, any pay you receive comes from PTO, an employer STD plan, or a state paid-leave program, not from FMLA itself.
Your job (or an equivalent one) and your group health coverage are protected during qualifying leave.
These numbers come directly from the Department of Labor's Wage and Hour Division, which wrote and enforces the law (dol.gov/agencies/whd/fmla). Sun Life can decide whether your specific medical evidence supports a qualifying leave, and it can manage the intake and paperwork, but it cannot shorten your 12-week entitlement, invent new eligibility hurdles, or deny you protections the statute already guarantees. See our FMLA eligibility guide for the full three-part test and our medical certification guide for what your doctor actually needs to submit.
If Sun Life Denies Your FMLA Claim
Ask Sun Life directly what's missing or why the claim was denied, incomplete medical certification and failure to meet the basic eligibility test are the most common reasons any administrator denies FMLA. You can typically submit additional medical documentation and ask for reconsideration; check your denial letter for your plan's specific appeal window, since that detail is set by your employer's plan rather than by a single fixed federal deadline.
If you believe your federal FMLA rights were violated, not just a claims decision you disagree with, but retaliation, interference, or an employer ignoring the law outright, you can file a free complaint with the DOL's Wage and Hour Division at 1-866-487-9243 or through dol.gov/agencies/whd/fmla. Our Department of Labor FMLA guide walks through exactly what the WHD investigates and how to file.
Frequently Asked Questions
What is Sun Life's role in my FMLA claim?
Sun Life is the third-party claims administrator many employers hire to process FMLA and disability paperwork. It collects your leave request, reviews your medical certification, and decides whether your absence qualifies, but the underlying 12-week entitlement and eligibility rules come from federal law, not from Sun Life.
How do I file an FMLA claim through Sun Life?
Tell your employer first, then contact Sun Life online through its member portal at sunlife.com or by phone. Sun Life's general Member Services line is 1-800-247-6875 (Monday-Friday, 8 a.m.-8 p.m. ET), though your employer may have assigned a separate dedicated claim-intake number, check your leave packet or ask HR.
Is FMLASource the same as Sun Life?
They're closely connected. Sun Life's absence management offering has operated through FMLASource, Inc. A company affiliated with ComPsych Corporation that handles day-to-day leave administration on Sun Life's behalf. You may see either name in your plan materials or on the claims portal; both refer to the same underlying process.
How long does Sun Life take to process an FMLA claim?
There's no single guaranteed timeline, it depends on your plan and how quickly your provider returns a complete medical certification. Plan documents we reviewed describe Sun Life aiming to issue a decision within about 48 hours of receiving a complete, certified medical form, but treat that as an example rather than a universal promise, and ask your HR team what turnaround your plan targets.
Does Sun Life decide whether I'm eligible for FMLA?
Sun Life evaluates whether your medical documentation supports a qualifying reason and manages the eligibility check your employer requires. But the eligibility test itself, 12 months of employment, 1,250 hours worked, and a covered employer with 50+ employees within 75 miles, is fixed by federal law, not by Sun Life.
Can my manager approve or deny my FMLA leave instead of Sun Life?
No. When an employer uses Sun Life for leave administration, your manager typically has no authority to approve, deny, or override an FMLA determination. Submit your certification directly to Sun Life, not to your manager, and expect the decision to come from Sun Life's claims team.
Does Sun Life also handle short-term disability?
Often, yes, many employers use Sun Life for both FMLA and short-term disability. They're separate claims that usually need to be filed separately, even though they can run at the same time. FMLA protects your job; your employer's STD plan (administered by Sun Life) may replace part of your wages, at a percentage and duration your employer's plan sets, not Sun Life.
What if Sun Life denies my FMLA claim?
Contact Sun Life to find out exactly what's missing or why the claim was denied, incomplete or unclear medical certification is the most common reason. You can generally submit more documentation and request reconsideration; check your denial letter for your plan's specific appeal deadline. If you believe your federal rights were violated, you can also file a complaint with the DOL's Wage and Hour Division.
What documents does my doctor need to send Sun Life?
Your health care provider completes a medical certification form describing your condition and how it affects your ability to work. Federal regulations generally require that you be given at least 15 calendar days to return a completed certification, and Sun Life's own plan materials reference this same window. See our medical certification guide for what the form actually asks.
Do I need a fitness-for-duty note to return to work?
Many plans administered by Sun Life require a fitness-for-duty certification from your provider before you're cleared to return from medical leave. This requirement can vary by employer and by the reason for your leave, so confirm what your specific plan requires before your expected return date.
Can I work another job while on FMLA leave through Sun Life?
Check your employer's specific policy. Plan documents we reviewed for at least one Sun Life-administered plan explicitly prohibit outside employment during a protected leave and treat it as grounds for termination. Policies like this come from the employer, not from FMLA itself, so don't assume every plan handles it the same way.
Does using Sun Life change how many weeks of FMLA I get?
No. Sun Life administers the claim, but it can't change your statutory entitlement. Eligible employees get up to 12 weeks of job-protected leave in a 12-month period, or up to 26 weeks for military caregiver leave, the same numbers apply whether your employer handles leave in-house or outsources it to Sun Life.
Key Takeaways
Sun Life is a claims administrator, often operating through FMLASource, Inc. It processes and decides claims but doesn't write FMLA law.
File by phone or online: Sun Life's general Member Services line is 1-800-247-6875 (Mon-Fri, 8 a.m.-8 p.m. ET); your employer may also have a dedicated claim-intake number.
Your doctor's certification goes to Sun Life directly, not your manager, and federal rules generally give you at least 15 calendar days to return it.
FMLA and STD are separate claims that run concurrently. Sun Life may handle both, but your employer's plan sets the wage-replacement percentage and duration.
Your 12-week (or 26-week military caregiver) entitlement is fixed by federal law. Sun Life can't shrink it or add eligibility hurdles the statute doesn't require.
If you believe your federal rights were violated, not just disagree with a claims decision, the DOL's Wage and Hour Division (1-866-487-9243) is the place to escalate.
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