A diagnosis shouldn't be a reason to cancel the trip. Below is what we've learned from carrying the cooler through TSA, EASA, and CAAC airports — country rules, packing tips, and a doctor's-note template you can hand to security.
Carry-on, every time.
Cabin only. The cooler and its lithium battery travel in the cabin — never in checked baggage. This is standard for any lithium battery, on any airline.
Personal item allowance. The cooler in its sling bag fits inside standard personal-item dimensions. It goes under the seat in front of you.
Declare at security. Tell the screening officer it's a medical cooler with prescription medication inside. Carry your prescription documentation and the doctor's-note template below.
Country and region rules.
United States — TSA
Medications and the devices that store them are exempt from the 3-1-1 liquids rule. Tell the officer at the bin you have medication; expect a brief swab test of the cooler or a visual inspection. The TSA officially welcomes notification — there's a "TSA notification card for travelers with disabilities and medical conditions" you can download from the TSA website and carry alongside your prescription.
Canada — CATSA
CATSA permits medically necessary liquids, gels, and medical devices in carry-on without volume restrictions. Declare the cooler at pre-board screening. Have your prescription label visible if possible.
United Kingdom — DfT / Heathrow, Gatwick, Manchester, Edinburgh
Insulin and other temperature-sensitive medications are exempt from the 100 ml liquids rule when accompanied by a prescription or doctor's letter. The cooler may be inspected separately. Allow an extra 5 minutes at security.
European Union — EASA
Member-state rules vary slightly but all follow EU Regulation 2015/1998: medical liquids and devices are permitted in carry-on with proof of need. A doctor's note in English plus the local language of your destination is the safest combination.
Australia — TravelSECURE
Medical liquids and the coolers carrying them are screened separately and permitted in cabin. Have your prescription paperwork accessible. Lithium batteries follow IATA carry-on rules.
China / Hong Kong — CAAC
Insulin and prescription cold-chain medications are permitted in cabin with a doctor's letter (Chinese or English). Lithium battery rules are stricter — keep yours within the IATA limit and carry the spec card included in the box.
Five things we've learned.
- Charge it the night before, then top it up at the gate. Most airports have outlets near gates now. You'll board with a full battery and a chilled cabin.
- Bring the car USB cable. Hotels and rental cars are unpredictable. A 12 V car USB outlet always works.
- Don't put it through the x-ray with the battery in. It's safe to, but TSA will sometimes ask you to remove the battery for a separate scan. Save the time and pull it out before the bin.
- Set your low alarm at 2 °C. Insulin damage from freezing is as serious as damage from heat. If you're flying somewhere cold, the heating mode keeps you out of trouble.
- Photograph your medication labels. If a pen breaks or a vial is lost in transit, a photo of the label gets a pharmacist on the other end moving fast.