Welcome and thank you for your thoughtful comment.

The Koran evidently says that a man must, at minimum, cover from the navel to the mid-thigh,

The Koran also strongly urges that all dress alike to stress equality.

Pretty much everyone will wear more layers underneath as the weather is cooler, often a pair of ankle length pants over underwear, but long underwear is not uncommon in cold areas.

As far as foreigners wearing the garb, it should be considered respectful to dress as those around you.

As several have pointed out, the main problem isn’t the locals, but the other ignorant expats.

Exactly what the style is will depend greatly upon where the wearer is from, traditionally, before mass production, Bedouin, like most people world-wide had distinctive styles by the tribe or village. This permitted an experienced person to identify where a person came from by small differences in style.

Note that during WWII the US OSS had a workplace in Canada which was capable of turning out an outfit which would match completely nearly any village in Europe, for use by spies.

And it was needed, as the Nazis were just as able to identify where you came from by your dress as any other people–and the SS and Gestapo were VERY good at spotting discrepancies..

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Logically, i would imagine that it would be strange for someone to inquire to guy whether or not he has Sunna, boxers or izar or anything at all, for that matter, under the Thobe. so in light of that i think if there are a significant populations that isn’t as dressed as everyone else, or even an individual doing this, no one would really know it, because I’m guessing no one would ask.

i also came across in a forum where a Swedish tourist over heard a barber mentioning quite a bit of men do go without modest coverings. in that conversation, another forumer ( probably Saudi) says its not likely to be true. It appears they came to a consensus that the barber knew the tourist was listening and made a statement for a shock factor for fun or amusement…

also are there variations on the thobe by region in the Kingdom? didn’t find much online in this respect. I have been doing research on history, traditional clothing, cuisine, etc on the peninsula. Just find it highly fascinating….

just wait for my qestion about Abaya( i will be more modest than i have been here)
thank you for you response, consideration and you understanding Bedu…

I tried to find out more about the “Sunnah” underpants but didn’t find much. What i did find falls in line with what ruman and others have mentioned; a cloth that covers the area between the navel and the below the thigh. Also, I tried to find if it was true that sometimes nothing
(no underpants) is worn under the Thobe/thawb but found a few sources saying that its highly unlikely because of the thin white fabric and it be transparent in the sun. a persons silhouette can be seen. Would this matter if the color of the thobe was a darker color? However as i have learned there are always exceptions to a rule. So do most men wear a lungi, slit-less boxers, or a izar as a common trend, culture/tradition or personal taste and a minority go “commando” from personal taste or on those especially unbearable hot days. would that be a correct assertion to make? also are thobes (with trousers) only made of cotton or are other materials used?

In light of all the above the thobe seems to be very comfortable to wear. It would be cool to own one.