How can I keep my Non-B visa from expiring when traveling to South Africa, and what are the implications for my infant's visa status?

If you have a single entry Non-B visa and plan to travel to South Africa, you'll need to obtain a re-entry permit to avoid your visa expiring while you're away. This permit can be obtained at the immigration office or at the airport, costing 1000 baht at the immigration office and 1200 baht at Suvarnabhumi Airport. Note that this re-entry permit does not extend your current visa duration; it merely allows you to return before the visa's expiration date. Regarding your 7-month-old baby, children under 15 are not charged for overstaying, and you would not incur fines for her overstay. Instead, you might consider applying for a 90-day Non-O visa for her upon your return, particularly if you plan to extend your own visa based on work.