Quick answer
A standard gel ice pack is treated as a liquid. Fully frozen, declared medical or baby ice packs are usually allowed in larger sizes — but you have to declare them at the start of the screening.
Once an ice pack starts to thaw, the 100ml rule applies. Bring it fully frozen or pack it in checked baggage.
Cabin vs checked baggage
| Type | Cabin | Checked |
|---|---|---|
| Standard gel ice pack | ≤100ml or in checked | Yes, unlimited |
| Medical (insulin, etc.) — declared | Yes, fully frozen | Yes |
| Baby food / breast milk pack — declared | Yes, fully frozen | Yes |
| Reusable cool block (large) | No | Yes |
Why was yours taken?
- It was over 100ml and you didn't declare a medical or baby use
- It had started to soften at the edges (treated as a liquid)
- Dry ice over the airline's limit (usually 2.5kg) and not vented
- The officer couldn't verify the medical declaration
International travel notes
The US (TSA), UK (DfT) and EU all allow medical and baby ice packs in larger sizes if declared and fully frozen. Australia, NZ and most of Asia apply the same logic but tend to be stricter at the point of screening.