This is a reply to my earlier email to NPS:

Limits4all,
I will see what I can do about putting a clear answer on our website, but
in the meantime, I can tell you that I have recently checked with the Chief
Ranger here at Amistad about this very issue because I have had several
calls regarding whether or not the laws have changed for people who launch
on the U.S. side of Lake Amistad and boat over to the Mexican side of the
lake. The new passport initiative that is taking effect in June does not
impact boaters here at the lake, only those people that cross as a port of
entry need to show a passport. As long as you stay on the lake and do not
step foot onto Mexico there is no issue for you. Of course, you still need
the Mexican fishing license, but that is all that is required of you.

Thank you for your interest in Amistad National Recreation Area and please
let me know if you have any further questions.

Casey Korth
Visitor Use Assistant
Amistad National Recreation Area
830-775-7491

That's what they had told me when I asked them. The WTTT championship tournament is down there in September. So, I needed to know the law too. I wasn't going to post on the other topic what I was told and get slammed. Glad they emailed you the answer I was told also.

WORD TO THE WISE!!!!!!!!!!!! GET IT IN WRITING!!!!!!!!PARK SERVICE HAS BEEN KNOW TO LIE WHEN THE THE TRUTH WOULD BE BETTER.
ASK ALL OF THE FOLKS AT BOX CANYON ABOUT THE LAW SUIT TO BE FILED CONCERNING LIES TOLD BY NPS. EMAILS DON'T COUNT

LARRY SCRUGGS

Don't know about the Parks service lying about anything, not sure why they would. The answers that The Hag and Limits4all got sounds reasonable, but I don't think the parks service is the one in charge when it comes to the border.

I think those decisions will be made by the INS.

INS and the fed govt set the passport laws, think you'd be smart to carry it. if ins/border patrol sees u on mex side and "meets" you at the beach you may have a problem.