Costco Mail Order is available to Medicare members with most plan types, but coverage and cost depend on your specific plan and pharmacy network

Costco Mail Order Pharmacy is not a Medicare plan itself — it is a pharmacy service that Costco offers to its members. Whether your Medicare plan covers prescriptions filled there depends on two things: whether your plan includes prescription drug coverage, and whether Costco Mail Order is in your plan's pharmacy network.

If you have a Medicare Advantage plan (Part C) that includes prescription drug coverage, or a standalone prescription drug plan (Part D), your plan has a list of pharmacies where you can fill prescriptions at the plan's negotiated price. Costco Mail Order is included in many of these networks, but not all. If it is in your network, you pay your plan's copay or coinsurance. If it is not, you pay the full price and may not get reimbursed.

If you have Original Medicare (Part A and B only) with no drug coverage, Costco Mail Order will fill your prescriptions, but Medicare does not cover them — you pay the full retail price out of pocket.

Key Takeaways

  • Costco Mail Order Pharmacy works with most Medicare Advantage and Part D plans, but you must check your specific plan's pharmacy network to confirm.
  • Your plan's official website or member handbook lists which pharmacies are in-network; calling the plan's customer service number is the fastest way to verify Costco Mail Order status.
  • If Costco Mail Order is in your network, you pay your plan's copay; if it is not, you pay full price and receive no Medicare reimbursement.
  • Costco membership is required to use Costco Mail Order Pharmacy, separate from your Medicare plan membership.

How to check if Costco Mail Order is in your plan's network

The most direct way is to call your Medicare plan's customer service number, which is on your insurance card or in your plan documents. Tell them you want to fill prescriptions by mail at Costco and ask whether Costco Mail Order Pharmacy is in your plan's network. They can answer in one call and tell you what your copay would be.

You can also check your plan's website. Most Medicare Advantage and Part D plans have a pharmacy finder tool where you enter "Costco" or search by location. Look for "Costco Mail Order" specifically, since some plans may include Costco retail locations but not the mail order service.

Your plan's member handbook also lists participating pharmacies, though the mail order section may be shorter than the retail pharmacy list. If you cannot find Costco Mail Order listed, that usually means it is not in your network.

What happens if Costco Mail Order is not in your plan's network

If your plan does not include Costco Mail Order in its pharmacy network, you have a few options. You can fill prescriptions at an in-network pharmacy instead and pay your plan's copay. You can also fill at Costco Mail Order and pay the full retail price out of pocket — Medicare will not reimburse you, even if you have drug coverage.

Some people choose to do this for certain medications if Costco's retail price is lower than their copay at an in-network pharmacy, or if they prefer mail order delivery. But this is your choice to make and costs you more than using an in-network pharmacy.

If you switch to a different Medicare plan during the annual open enrollment period (October 15 to December 7), you can choose a plan that does include Costco Mail Order if that matters to you. When comparing plans, check the pharmacy network as part of your decision.

Medicare Advantage plans versus Part D standalone plans

Medicare Advantage plans (Part C) bundle hospital, doctor, and prescription drug coverage into one plan. If your Medicare Advantage plan includes drug coverage, Costco Mail Order may be in that network. You would call the Medicare Advantage plan's number to check.

Part D standalone plans cover only prescriptions and work alongside Original Medicare. If you have Original Medicare and a Part D plan, you would call your Part D plan to ask about Costco Mail Order. Part D plans are offered by private insurance companies, and each one maintains its own pharmacy network.

Some people have both — for example, a Medicare Advantage plan for medical care plus a separate Part D plan for prescriptions. In that case, check with whichever plan you want to use for mail order prescriptions.

Costco membership requirements

Using Costco Mail Order Pharmacy requires an active Costco membership, separate from your Medicare plan. You do not need to be a Costco member to use Costco's in-store pharmacy, but mail order is only available to members.

Costco offers different membership tiers. The basic membership level is sufficient for mail order pharmacy use. If you already shop at Costco, your current membership works. If you do not have a membership, you would need to purchase one before filling prescriptions by mail.

How mail order prescriptions work with Medicare

When you use Costco Mail Order and your plan covers it, the process is straightforward. You provide your prescription to Costco Mail Order (by phone, online, or by having your doctor send it directly). Costco fills it, ships it to your home, and you pay your plan's copay when you receive the package or at the time of order, depending on how Costco processes it.

Mail order typically takes 7 to 14 days from the time Costco receives your prescription. This works well for medications you take regularly and can plan ahead for, but not for urgent prescriptions you need right away. For urgent needs, you would fill at a retail pharmacy instead.

Keep track of when your mail order prescriptions will arrive so you do not run out. Some people set up automatic refills through Costco to avoid gaps in their medication.

Frequently Asked Questions

Can I use Costco Mail Order if I have Original Medicare with no drug plan?

Yes, but Medicare will not cover the cost. Costco will fill your prescriptions, and you pay the full retail price out of pocket. Original Medicare does not include prescription drug coverage unless you add a Part D plan.

What if my plan says Costco is in-network but Costco Mail Order is not?

Some plans include Costco retail pharmacies but not the mail order service. When you call your plan to verify, specifically ask about "Costco Mail Order Pharmacy" or "Costco mail order" to avoid confusion. Retail and mail order are separate services.

Do I pay the same copay for mail order as I would at a retail pharmacy?

Usually yes, but check your plan documents or call your plan to confirm. Some plans charge the same copay for mail order and retail, while others may have different copays for 30-day versus 90-day supplies. Mail order is often used for 90-day supplies, which may have a different copay structure.

Can I switch to a plan that includes Costco Mail Order if mine does not?

Yes, during the annual open enrollment period (October 15 to December 7) you can switch to a different Medicare Advantage or Part D plan. When reviewing plans, check the pharmacy network to see which ones include Costco Mail Order. You can also switch if you have a may have access to life event outside of open enrollment.

What if I move to a different state — will Costco Mail Order still work?

Costco Mail Order ships nationwide, so location is not a barrier. However, your Medicare plan may change if you move, and a new plan may have a different pharmacy network. After you move, check with your new plan to confirm Costco Mail Order is still covered.