Are coin cell batteries treated the same as spare lithium-ion batteries?

No. Spare lithium-ion batteries (like 18650s) have a 100 Wh limit that requires attention at security. Button/coin cells are lithium metal batteries with such a tiny lithium content — typically 0.1–0.3 grams versus the 2-gram restricted threshold — that they're effectively unrestricted.

Can I pack a pack of spare watch batteries in checked luggage?

It's better not to. FAA guidance treats all loose, uninstalled lithium batteries as carry-on only, even very small ones. A battery already installed in a watch or device can go in checked baggage without issue.

Button Cell Batteries

Small lithium coin/button cell batteries are allowed in carry-on and checked bags — their lithium content is far below the limits that restrict larger spare lithium batteries.

Carry-on

Allowed

Checked

Allowed with conditions

Carry-on details

Allowed. Button and coin cell batteries (like the CR2032 in a watch or key fob) contain only about 0.1–0.3 grams of lithium — a small fraction of the 2-gram lithium metal limit that applies to spare batteries. They're allowed in carry-on with no watt-hour or quantity limit, whether loose or installed in a device.

Checked-bag details

Allowed with conditions. A button cell installed in a device (a watch, key fob, or small toy) can go in checked baggage with the device. Loose spare button cells, like all uninstalled lithium batteries, technically fall under FAA's carry-on-only rule for spare batteries — pack extras with your carry-on rather than checked bags to be safe.

Special instructions

This applies to lithium coin cells (the CR/BR-prefixed types, including CR2032 and CR2025). Non-lithium button cells used in watches and hearing aids, such as silver-oxide (SR-prefixed) or alkaline (LR-prefixed) cells, contain no lithium at all and carry no restrictions whatsoever. If carrying loose spares, keep them in their original blister packaging or a case so the terminals can't touch metal.

Related rules

Lithium Battery & Power Bank Rules

FAQ

Are coin cell batteries treated the same as spare lithium-ion batteries?: No. Spare lithium-ion batteries (like 18650s) have a 100 Wh limit that requires attention at security. Button/coin cells are lithium metal batteries with such a tiny lithium content — typically 0.1–0.3 grams versus the 2-gram restricted threshold — that they're effectively unrestricted.
Can I pack a pack of spare watch batteries in checked luggage?: It's better not to. FAA guidance treats all loose, uninstalled lithium batteries as carry-on only, even very small ones. A battery already installed in a watch or device can go in checked baggage without issue.

Related items

Sources: TSA — What Can I Bring?, FAA — PackSafe (Hazardous Materials) · Last verified: 2026-08-01

Final decision rests with the security officer at the checkpoint.