If you are a USA citizen or resident, you an easily go to Cuba via Mexico. However, you are still subject to the current regulations governing American resident and citizen travel to Cuba, as set forth by the Office of Foreign Assets Control of the U. S. Treasury.

Though nobody I know of recently (I do know people who traveled to Cuba via Canada and Mexico who were fined by the US Government) has been fined, I'd not put too much reliance on what the current Administration might or might not do vis a vis Cuba.

Read the Wikipost at the top of this page in the thread, as well as the thread. http://www.flyertalk.com/forum/cuba/...nces-only.html.

If you are a legal USA citizen or resident, you must:

1) You must declare you visited Cuba otour US Customs and Immigration form, or if asked where you've visited. US ICE and CBP don't largely seem to care, but hiding your visit technically violates 18 USC 1001*, with a potential 5 years of prison and large fine (ask Martha Stewart how that law works). At least you may well lose any Global Entry and PreCheck you may have.

*which generally prohibits knowingly and willfully making false or fraudulent statements, or concealing information, in "any matter within the jurisdiction" of the federal government of the United States, even by mere denial.

2) All Americans traveling to Cuba without a specific license must be at least able to self declare their visit was under one of the twelve categories okayed by OFAC.

This may seem okay to be taken lightly, but we are talking about Federal laws here. And yes, I have been to Cuba; yes, I know people who were found out and sanctioned for unauthorized visits to Cuba.