bamafan
Contributor
In the last year or so Mexico has started to follow the TSA guidelines on lithium batteries. There was a sign in the Cancun or maybe Cozumel airport stating that lithium batteries were to go into your carryon. I just flew out of Cancun a few weeks ago with a bunch of lithium batteries in my carryon and it was fine. My buddies flew out of Cozumel and they didn't have any issues either with them in your carryon. You can ask at the ticket desk where you drop off your checked baggage. Worse case scenario you put them in the check bag then swap to carryon at immigration in the US if you have a connecting flight.