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How to ship breast milk safely

Aligned with CDC guidance; not medical advice · Updated July 2026

Quick answer: Ship milk frozen solid, overnight, in a styrofoam-lined box with dry ice (roughly 5 to 10 lbs per 24 hours of transit) or a specialty service like Milk Stork that handles everything. Label the package per carrier dry-ice rules, ship early in the week, and have someone ready to freeze it on arrival.

The DIY overnight method

  1. Freeze bags flat and solid for at least 24 hours beforehand.
  2. Pack tightly (fullness slows thawing) in a styrofoam cooler inside a cardboard box, dry ice above and below the milk with cardboard between, since direct contact can crack bags.
  3. Overnight it Monday through Wednesday only, so a delay cannot strand the box over a weekend.

Handling dry ice: gloves, ventilation, and the carrier's hazmat labeling rules (UN1845, weight declared).

Or make it someone else's job

Services like Milk Stork ship you a pharmaceutical-grade cooler that keeps milk cold or frozen for days, with prepaid overnight return. Many employers cover it as a travel benefit; asking HR costs nothing and the yes rate is higher than moms expect.

Milk First tracking fridge, kitchen freezer, and deep freezer totals

In Milk First

Track every location you actually use: fridge, freezers, cooler bag, daycare. Moving a bag switches its clock automatically (freezer to fridge starts the 24-hour thaw window), and app labels match what you sharpie on the bag.

Move milk between locations · Match app labels to sharpie labels

Milk First keeps every date, clock, and rule from this page automatic, so 3 AM you never has to remember any of it.

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