Some links that give suggestions on this. Looks like they recommend that you get them about 4-6 weeks in advance. But even if you can't, it's best that you get them nonetheless. I'd recommend the Hep shots, even if you aren't traveling. www.netdoctor.co.uk/ate/infections/202229.html www.doctortravel.ca/index.php?page=central-america-and-mexico wwwn.cdc.gov/travel/destinationMexico.aspx (The bottom one is the CDC's website for mexico. You'll have to copy and paste since it has an "n" following the "www" (not a typo)) Personally, we've never made a special trip to the doctor for shots prior to our trips. But we've had Hep shots previously because either our employment or school required them.