To ship frozen food, pre-freeze it solid, pack it in an insulated cooler inside a sturdy cardboard box with enough dry ice or frozen gel packs for the whole trip, label the box correctly (dry ice packages need “Dry Ice, UN1845” and the net weight), and send it by an overnight or 2-day service early in the week. The food should still have ice crystals, or be at 40°F or colder, when it arrives.
The rules that trip people up are the dry ice ones. USPS caps dry ice at 5 pounds per package when the package flies, and UPS treats dry ice differently on ground and air routes. This guide walks through packaging, coolant amounts, labeling, carrier choice and timing, and it’s the starting point for the rest of our guides to shipping perishables and food.
Table of Contents
- What do you need to ship frozen food?
- How do you pack frozen food step by step?
- Should you use dry ice or gel packs?
- How much dry ice do you need?
- What are the USPS rules for frozen food and dry ice?
- What are the UPS rules for shipping with dry ice?
- Which shipping service should you use for frozen food?
- When is the best time to ship frozen food?
- What affects the cost of shipping frozen food?
- What should the recipient do when it arrives?
- Guides for specific frozen and perishable foods
- Frequently Asked Questions
What Do You Need to Ship Frozen Food?
You need four things: an insulated container, a strong outer box, a coolant, and the right labels. Skimping on any one of them is the usual reason a frozen shipment arrives soft.
- Insulated container. An expanded polystyrene (EPS foam) cooler with walls about 1.5 to 2 inches thick handles most overnight and 2-day trips. Reusable molded or polypropylene coolers cost more but survive many shipments.
- Corrugated outer box. Carriers expect the foam cooler to sit inside a cardboard box. Foam alone cracks on conveyors and can’t hold a label well.
- Coolant. Dry ice keeps food hard-frozen. Frozen gel packs keep food cold but won’t hold it at freezer temperature for long.
- Inner packaging. Vacuum-sealed or zip-top bags keep food dry if condensation forms, and a plastic liner contains any leak.
- Labels and tape. “Perishable” and “Keep Frozen” markings, dry ice markings if you use it, and pressure-sensitive packing tape.
| Container type | Durability | Best for | Watch out for |
|---|---|---|---|
| EPS foam cooler in a box | Usually single-use | One-off gifts and occasional shipments | Cracks if the outer box is too loose |
| Polypropylene or molded reusable cooler | Many trips | Businesses that ship every week | Heavier, so billable weight goes up |
| Insulated liner or foil bubble pouch | Single-use | Short overnight trips, cold rather than frozen items | Too little insulation for 2-day frozen shipments |
How Do You Pack Frozen Food Step by Step?
Good packing does more than any upgrade in shipping speed. Work fast and have everything ready before you take the food out of the freezer.
- Freeze the food rock-solid. Freeze it at 0°F or colder for at least 24 hours. Colder food has more “thermal reserve” and stays frozen longer.
- Seal it. Vacuum-seal or double-bag each item so moisture and odors stay contained.
- Line the cooler. Put a plastic liner or bag inside the foam cooler to catch condensation or leaks.
- Load coolant and food. With gel packs, put frozen packs on the bottom, around the sides and on top of the food. With dry ice, wrap the blocks in newspaper or kraft paper and place them on top of the food, because cold air sinks. Never let dry ice touch bare food or the plastic liner.
- Fill empty space. Crumpled paper or more coolant fills the gaps. Air pockets warm up quickly.
- Close the cooler without sealing it airtight. If you use dry ice, the lid has to let carbon dioxide gas escape. Don’t tape the foam lid shut.
- Box and tape. Set the cooler in a snug corrugated box and tape the box seams. A box this size is easy to undercount, so measure it for dimensional weight.
- Label and ship the same day. Add the markings below and hand the package to the carrier before the day’s cutoff.
Different foods have different needs. Our step-by-step guide to shipping perishable food safely covers refrigerated items alongside frozen ones, and desserts such as cheesecake, shipped frozen for safe delivery, follow the same cooler-and-coolant method.
Should You Use Dry Ice or Gel Packs?
Use dry ice when the food has to stay hard-frozen, such as ice cream, frozen meat or seafood, or any trip longer than a day. Gel packs work for cold-but-not-frozen items and for short overnight trips where some softening is acceptable.
Dry ice is frozen carbon dioxide at about -109°F. It sublimates straight into gas instead of melting, so nothing gets wet, but the gas has to vent and the package becomes a regulated shipment. Gel packs are frozen water-based gel. They’re unregulated, reusable and safe to handle, but they warm up toward 32°F and above as they thaw.
| Factor | Dry ice | Frozen gel packs |
|---|---|---|
| Keeps food hard-frozen | Yes | Only briefly |
| Typical trip length | Overnight to 2 days, longer with more ice | Overnight |
| Carrier regulation | Hazardous material (Class 9, UN1845) on air routes | None |
| Packaging rule | Must vent, can’t be sealed airtight | Leak-proof bag recommended |
| Handling | Insulated gloves, ventilated area | No special handling |
| Best for | Ice cream, meat, seafood, frozen meals | Baked goods, cheese, cold produce |
Buy dry ice the same day you pack, and handle it with gloves. Many grocery stores sell it by the pound. Don’t store it in a sealed cooler at home or ride with it in a closed car.
How Much Dry Ice Do You Need?
A common starting point is 5 to 10 pounds of dry ice for each 24 hours in transit, for a mid-size cooler. Adjust it for cooler size, wall thickness and the weather. Because dry ice keeps sublimating from the moment you buy it, add a buffer for the time it sits in your freezer and on the truck.
| Transit time | Coolant plan | Insulation |
|---|---|---|
| Overnight | Gel packs for cold items, or about 5 lbs of dry ice for frozen items | Standard foam cooler |
| 2 days | About 10 lbs of dry ice (more in summer) | Thick-walled foam cooler, minimal empty space |
| 3 days or more | Not recommended for frozen food. If unavoidable, plan for a large dry ice load on a surface-only route | Premium or double-walled cooler |
Remember the carrier limits before you load more. A package that travels by air through USPS can hold no more than 5 pounds of dry ice, so a large load means either a surface service or a smaller, better-insulated box.
What Are the USPS Rules for Frozen Food and Dry Ice?
USPS accepts frozen food domestically. Dry ice is only allowed as a coolant for the item inside, and dry ice can’t go in international mail at all. The rules come from USPS Publication 52, Packaging Instruction 9A.
- Air transport limit: no more than 5 pounds of dry ice per package moving by air. Priority Mail Express and Priority Mail usually fly, so plan on this limit for those services.
- Air markings: “Dry Ice, UN1845” or “Carbon Dioxide Solid, UN1845,” the net weight of the dry ice, and the name of the contents being cooled (for example, “frozen steaks”) on the address side, plus a Class 9 hazard label.
- Surface packages: mark them “Surface Only” or “Surface Mail Only” along with the UN1845 marking. Surface pieces must never be routed by air.
- Venting: the package must let carbon dioxide escape, and fiberboard boxes need enough insulation that condensation doesn’t soak the carton.
Food sent through USPS travels at the shipper’s risk, so packing and speed are your protection. Our explainer on whether you can send food in the mail covers the general USPS food rules, including which items need refrigeration and which can go in a plain box.
What Are the UPS Rules for Shipping with Dry Ice?
UPS doesn’t regulate dry ice in UPS Ground shipments within the 48 contiguous states, so those packages go out like any other Ground package. Dry ice shipments to or from Alaska, Hawaii, Puerto Rico and Avalon, California must go as air shipments instead.
Air shipments with dry ice are regulated. Mark the box “Dry Ice” or “Carbon Dioxide, Solid,” UN1845, and the net weight in kilograms, and add the Class 9 label where required. Larger dry ice quantities by air require a UPS hazardous materials agreement. Check UPS’s coolants and refrigerants guide for the current per-package threshold before you ship.
| Requirement | USPS | UPS |
|---|---|---|
| Dry ice by air | Up to 5 lbs per package | Regulated, with an agreement required above UPS’s small-quantity threshold |
| Dry ice by ground | Allowed when marked “Surface Only” | Not regulated for UPS Ground in the 48 contiguous states |
| Key marking | Dry Ice, UN1845, net weight, contents name | Dry Ice or Carbon Dioxide, Solid, UN1845, net weight in kg |
| International | Dry ice prohibited | Depends on destination and service |
| Venting | Required | Required |
Every frozen box should also say “Perishable” and “Keep Frozen” on more than one side, and “This Side Up” arrows help keep the dry ice on top.
Which Shipping Service Should You Use for Frozen Food?
Choose the slowest service you’re confident your coolant can outlast, and no slower. For most frozen food, that means overnight or 2-day.
| Service | Delivery commitment | Fits frozen food when |
|---|---|---|
| USPS Priority Mail Express | Overnight to 2-day, money-back guarantee on most routes | You need the fastest USPS option. 5 lb dry ice limit applies |
| USPS Priority Mail | 1–3 business days | Short distances with ample gel packs or up to 5 lbs of dry ice |
| UPS Next Day Air | Next business day, time-definite | Ice cream, seafood and long distances |
| UPS 2nd Day Air | Second business day | Well-insulated boxes with enough dry ice for 48 hours |
| UPS Ground | 1–5 business days by distance | Nearby destinations that arrive in 1–2 days. Unregulated dry ice in the 48 contiguous states |
UPS Ground is often the smart frozen-food choice inside a region. A package that reaches its destination in 1 or 2 ground days can carry a heavy dry ice load without air rules, while a coast-to-coast box needs air service. Use the UPS ground time-in-transit map or a rate quote to see how many days your route takes before you pick.
ParcelPath lets you compare UPS and USPS side by side with discounts of up to 85% off UPS and up to 89% off USPS. It’s free, with no subscription or per-label fee. Enter your box’s weight and dimensions in the ParcelPath rate calculator to see what overnight, 2-day and ground cost for your exact route, and print the label at home, or use the UPS Mobile Barcode at a UPS Store if you don’t have a printer.
When Is the Best Time to Ship Frozen Food?
Ship Monday through Wednesday, early in the day. A package that misses Friday delivery can sit in a warm facility over the weekend, which is long enough to thaw most frozen boxes.
- Beat the cutoff. Drop off or schedule a pickup in the morning so the package moves that day.
- Check the weather at both ends. Heat waves call for more dry ice or a faster service. Winter storms cause delays that coolant has to cover.
- Avoid holidays. Carrier networks slow around late November through December and before food-heavy holidays, so add a day of coolant or ship a week earlier.
- Tell the recipient. Send the tracking number so someone is home to bring the box inside right away.
What Affects the Cost of Shipping Frozen Food?
Five things drive the price: speed, distance, weight, box size and coolant. Air services cost far more than ground, and the cooler plus dry ice can add several pounds of billable weight before the food is even in the box.
- Service level: overnight costs the most, and 2-day and regional ground are where most savings come from.
- Dimensional weight: a big foam cooler is light but bulky, so carriers may bill it by size. A cooler sized tightly to the food keeps the billable weight down.
- Coolant weight: dry ice and gel packs count toward the package weight.
- Distance: ground service to a nearby state is far cheaper than air across the country.
Businesses that ship frozen goods often, or by the pallet, should also read our guide on ways to cut refrigerated shipping costs, which covers temperature-controlled freight. To estimate a parcel before you buy coolant, our shipping calculator guide explains how weight, zone and dimensions combine into a price.
What Should the Recipient Do When It Arrives?
Open the box right away and check the food. USDA guidance says frozen items should still have ice crystals, or be refrigerator-cold at 40°F or below when checked with a food thermometer. Anything warmer than 40°F shouldn’t be eaten or tasted.
- Move the food straight into the freezer or refrigerator.
- Let leftover dry ice sublimate outdoors or in a ventilated room. Never handle it bare-handed or put it in a sink or a sealed container.
- If the package was late or the food is warm, photograph the contents and the label, then contact the shipper. If the shipper bought insurance, the photos support the claim.
Guides for Specific Frozen and Perishable Foods
Each food has its own packing quirks. These guides apply the methods above to specific items:
- How to ship seafood: fresh and frozen fish and shellfish on dry ice or gel packs.
- How to ship cheesecake: frozen-solid desserts in insulated boxes.
- How to ship baked goods: cookies, breads and cakes that ship cold or at room temperature.
- How to ship fruit to another state: agricultural rules for fruit crossing state lines.
- How to ship strawberries: keeping delicate berries cold and uncrushed.
- How to ship honey: leak-proof packing for jars.
- Shipping coffee: whole bean and ground coffee that doesn’t need refrigeration.
- Breast milk shipping: frozen breast milk with dry ice.
For everything else that ships, browse the full library of ParcelPath shipping resources or head back to the ParcelPath home page.
Frequently Asked Questions
How long does frozen food stay frozen when shipped?
With a well-insulated foam cooler and enough dry ice, frozen food generally stays frozen for 24 to 48 hours. Gel packs alone keep food cold for roughly a day but let it soften. Ship overnight or 2-day early in the week, and pre-freeze the food at 0°F or below so it starts as cold as possible.
Can you ship frozen food through USPS?
Yes. USPS accepts frozen food domestically, packed in an insulated container with dry ice or gel packs. Packages traveling by air, which usually includes Priority Mail and Priority Mail Express, can hold up to 5 pounds of dry ice and need “Dry Ice, UN1845,” the net weight and a Class 9 label. Dry ice can’t go in international mail.
How do you ship frozen food without dry ice?
Freeze several gel packs solid for at least 24 hours, line an insulated foam cooler with them on the bottom, sides and top, pack the pre-frozen food tightly in between, and fill every gap. Ship overnight early in the week. Expect the food to arrive very cold rather than rock-hard, so this method suits short trips and sturdy items.
How do you label a frozen food package with dry ice?
Mark the address side “Dry Ice, UN1845” or “Carbon Dioxide Solid, UN1845,” write the net weight of the dry ice, and name the contents being cooled. Air packages also need a Class 9 hazard label, and USPS surface packages need “Surface Only.” Add “Perishable” and “Keep Frozen” markings on several sides of the box.
What is the cheapest way to ship frozen food?
The cheapest safe option is usually the slowest service your coolant can outlast. For nearby states that’s often UPS Ground, which delivers in 1 to 2 days and doesn’t regulate dry ice in the 48 contiguous states. Keep the cooler tightly sized to limit dimensional weight, and compare discounted UPS and USPS rates before you buy a label.
Sources
- USPS Publication 52, Packaging Instruction 9A: Dry Ice
- USPS Publication 52, Section 349: Miscellaneous Hazardous Materials (Class 9)
- UPS: Shipping with Coolants and Refrigerants
- USDA: Mail Order Food Safety
Part of our Perishables and Food guide. Related: Shipping Resources, Shipping Coffee.
