Actually, the passport (for US citizens going into Mexico) the passport must be valid through the date you plan to return to the US.Your passports just need to be valid when you depart for Mexico.
https://travel.state.gov/content/passports/en/country/mexico.html
Actually, the passport (for US citizens going into Mexico) the passport must be valid through the date you plan to return to the US.
Well, yes. But, it also must be valid on the day you return to the US.From the state dept link s/he gave it’s only required to be valid upon entry.
While some countries require a passport be valid fir six months from date if entry, I don't believe Mexico is one of them. In any case, coming off of the cruise ship for a one day excursion shouldn't be a problem, it is pretty clear you do not intend to stay.