Can children under 14 stay on their parents' tourist visa in Thailand, and what are the costs for a visa run?

Okay, lets sort this out

@Louise ************

you need to STOP thinking of the 30 day extension you can get from the immgration office as part of ANY entry stamp. It is not, it is sold separately at the immigration office and has NOTHING to do with how many days you get when you stamp in.

You also need to understand the difference between

a 30 day visa exempt entry stamp <- which has that catchy name because you showed up here without a visa in your passport and were stamped in for free on the visa exempt entry program for 30 days.

AND

a tourist visa <- which you BUY from a thai consulate in another country and which gets you stamped in for 60 days when you enter thailand.

Both of those options to enter the country can be extended for 30 days at the immigration office for 1900baht.

One last thing is, you need to know the difference between a border bounce <- where you go to the border, stamp out of thailand, stamp in&out of another country and stamp back into thailand to get a 30 day visa exempt entry stamp (which you can do by land TWO times in a year) and a visa run <-which is where you go to a thai consulate in another country and BUY a visa for thailand.

I think a LOT of your confusion is caused by your mis-use of the terms and a lack of understanding what it is you're actually wanting to do.

Good Luck (y)

The cost of a run to a border, and the visit to a Thai consulate to get a tourist visa would largely depend on where you are in Thailand.

With a UK passport, you can do a border run (leave and come back) and get a thirty day Visa Exempt stamp. But you can extend that at an immigration office within the Kingdom for an additional thirty days. I know nothing about teenager visas.

You or your children can not get a tourist visa at the border. Foreign children official need a visa to stay inside Thailand, but till the age of 15 years old they will not get fined for overstay. As this page is only for Thai Visa advice we can not help you with the second part of your travel question. Google of tour office are much better in that.