How long can an Italian tourist stay in Thailand without a visa when crossing the land border?

@Dome *****

only if the vehicle is allowed to cross the border. Even then, it has to be any border other than Poipet/Aranyaprathet. This is because at this crossing, only the driver is allowed to use the car queue. Other crossings generally don't even have a dedicated car queue, although they do usually have a booth for drivers where forms have to be filled out and your passport and that of accompanying passengers can be stamped in there too.

@Steve ******

there used to be a lot of "beef" between the two sides, but this has now mostly been resolved. An online war of words between Thai and Khmer netizens continues but at this point, there is as much if not more online flaming between Thailand and Laos and Thailand and Vietnam. If you can understand Thai, you'd easily be able to find thousands of YT videos where such tensions become apparent especially in the comments section.

On a government to government level, no major issues anymore.

@Stuart ********

you mean Aranyaprathet? Poipet officials on the Cambodian side can be very corrupt and not the friendliest, but they rarely reject anyone from entering. Whereas Aranyaprathet officials on the Thai side often do. Waiting times in the hall are often long.

My advice on that crossing is not to use it if you're doing a border run. It's fine for those who arrive by car and use a separate car lane (but this is only allowed for the driver so you'd have to be traveling alone) and anyone who is on an extension of stay.

Tourists should use the bus (Siem Reap- Bangkok or Phnom Penh-Bangkok).

Everyone else should consider entering Thailand at any other border crossing.

@Robert ***********

Thailand and Cambodia are on pretty good terms at the present time. A remarkable turnaround from the low point in relations reached in 2011.

Thai immigration at Aranyaprathet being difficult stretches back years and has nothing to do with Cambodia, but rather, visa runners using it. They want to clamp down on that.

@Stuart ********

Maybe more so, because Thailand and Cambodia not so friendly?