I noticed a few people questioning if Thai Boat noodle soup is the same as Vietnamese Pho, or is there any difference.
So I will just speak of my knowledge and experience with the difference of these dishes. And I will speak specifically more about Street vendors in the two different countries and how they prepare and serve these two, not speaking outside of Thailand or Vietnam or the subtle Regional differences on each dish. I will speak more about the most common boat noodle you will find in Thailand.
Neither one is really healthier than the other, and not all Thai Boat noodle is spicy at all, it is up to the vendor who is making it and your taste you can say phonetically "my pet" to the Thai Boat noodle vendor and they will not add any hot spicy dried chili powder or fresh chillies to it, the base broth of Thai Boat noodle is very rarely pre spiced to be hot, that is added at the end if you wish for your dish to be hot. But if you are in isaan Thailand in the east or the very far north provinces, like Chang Mai Thailand or Chiang Rai Thailand, then you may get a broth that is already very hot and spicy because in that region they very much prefer everything pretty damn hot lol. But both broths, Boat noodle and Pho have very different ingredients, both to the broth and the additives they use in the dish right before serving it. The Thai Boat noodle that I prefer is not hot at all, but has a rich earthy minerally flavor to it, with a lot of the mineral flavor coming from the fresh blood added right at the end. And the perfectly balanced layering of flavors In Thailand. the standard boat noodle is done with pork, as beef is more expensive and harder to come by, and is much lower quality beef then let's say you would find in America, or Japan. it is usually served with mixtures of pork meat, liver, & lung, processed pork balls, and sometimes an option of chicken feet. but each of these are added to the broth at the end right before it goes in your bowl, heated in a cage well dipped into the large 2 or three-section Kettle pot. One is broth, one is used to heat the meat in a cage, and one if a 3 section will have a broth for the vegetables and noodles to be heated in, if it's only a 2 Section Pat than the meat vegetables and noodles will be heated in that second Broth in a cage, the primary broth for the soup base is always separate, from the ingredient heating section. and the blood is added to your bowl after the very hot borth and ingredients have been put in your bowl, right before serving it to you, the fresh Pig's blood then Cooks by the heat of the broth in your bowl by the time it gets to you within seconds and turns brown. you choose what proteins you want in your boat noodle. As well as the available vegetables that can be added to the dish and the type of noodle you want. Beef boat noodle is served in Thailand the same way, most vendors usually make the base broth for beef a little different with its ingredients to accentuate the flavor of the beef rather than pork. And the blood then is fresh cows blood added at the end just like the pork version. Vietnamese however don't really have a name for Thai Boat noodle because it is not part of their culture, simply in Vietnamese it would be rice noodle soup and the type of protein, but the base soup broth is made very differently in both cultures. As well as the preparation of the protein can be very different as well, and what part of the animal that protein was cut from. In Thailand if you find someone selling Pho, they simply call it pho, and name the protein they want in it and if there is different noodle options they will pick the noodle they want and speak in Thai. I have traveled quite extensively in both Thailand and Vietnam, both cultures have a beef or pork noodle soup not to be confused with Thai boat noodle soup, Thai regular noodle soups with whatever protein are much more similar to Pho, Thai beef Boat noodle is not the same as Thai beef soup, and this is one of my favorite dishes of all so I try it everywhere I see it, and committed a lot of time to learning to prepare this dish myself. I have never really seen Thai Boat noodle authentically made in Vietnam, I have seen pho soup base used but none of the additives like the blood, I have seen a few sit down eat in restaurants in Vietnam non street vendor Style that advertise Thai Boat noodle but again tend to be using a pho base broth, which is much closer to a regular Thai beef noodle soup.
I did find one vendor in the old Saigon now called Ho Chi Minh City, that was actually a Thai family who was making boat noodle very authentically. But I found that the exception not the rule. Seems to be very hard to come by an authentic boat noodle in Vietnam. Regionally in Thailand boat noodle can taste very different from one area of Thailand to another. I noticed in the north of Thailand they tend to add Chinese five spice to the base broth, and star anise. After a lot of research I have found this was not as close to the original way of making it in the fishing communities where it originated from, the Chinese five-spice came with Chinese influence from the north. If you ever find yourself in Bangkok try visiting the northern most District called Sai Mai, as the taxi drives down saimai Road, stop at soi 43, soi means side road, then walk a half a block back towards soi 41, you will see the family vendor with the thatched and corrugated metal roof over the eating area and right up front will have the customary cooking area, with a small wooden boat holding the cooking pots and everything, this is the Thai way of advertising boat noodle soup vendors. Give it a try, great Thai Boat Noodle at that vendor, one of the best I have found, and made by a family who has made that dish for over five + generations, and they come from the fishing Community where boat noodle originated. They make a truly Master dish broth at that one, and they only offer pork not beef but they offer you the pork meat from the butt or the front leg of the pig, the pig liver, and the lungs, are the protein options and chicken feet because many Thai's like it, as well as the processed pork balls. You can pick which meat you want or all of them in the dish if you wish. They only offer 2 types of rice noodle, the very thin rice noodles phonetically sounded "SenMe" my favorite, and rice stick noodles that are very similar to pad thai noodles in appearance. If you don't want it spicy at all just say phonetically "My Pet" that means not hot, if you want it hot she will ask you by saying in Thai " Pet or Pet Pet" the vendors normally go by five distinct levels of heat 1-5, you can pick your level simply by replying "Pet" and nodding your head yes, and holding up 1-5 fingers for the level of hot your looking for, but I warn you especially with Americans most Americans can't handle above 1* or 2* at most lol. Best to try without any heat your first bowl, then if you like, order the next Bowl 1* then 2* and so on until you reach the level you can handle. The bowl of normal pork boat noodle at the vendor, with only one type of protein is literally 15 baht, a bowl with Pork meat, and processed pork balls like I like is only 20 baht. And a bowl with all the different types of protein in it, pork meat, processed pork ball, pig liver, and lungs, is 30 baht. Add 5 baht for chicken feet. The daughter of the father speaks a little broken English, but this vendor is more for Thai people than tourist and is one of the Hidden holes in the wall that most tourists would never know about. But they are very highly regarded by the Thai's that live in that area, all Thai's in Sai Mai know of this vendor. I normally eat 4 to 5 bowls when I eat there. It is sooo good ;) My max was 9 bowls once lol, I was having a little competition racing my wife's cousin to see who could eat the most lol, he won at 14 bowls lol. We call him Thai giant because he was 6'6" at age 15 at the time, now he is 6"8' today at 25 years old lol. Biggest Thai man you will ever see lol.
If your in Thailand and want a dish closer to Vietnamese Pho, try a simple Thai beef noodle or pork noodle soup. That is closer.
Boat noodle is very distinctively different.
My favorite boat noodle especially at the vendor I listed above is done with the "SenMe" thin rice noodles, not hot "My Pet" with the green being Morning Glory water Vine, the hollow tubes with the leaves cut up. And the pork meat from the butt, and the processed pork balls, and of course it would not be boat noodle without the fresh blood. On the side is always soybean sprouts on the table, as well as Thai basil leaves, add if you like. I order the glass bottle of sweet Lipton tea as my drink. And of course I ordered the little bowls stacked on top of each other with the white creamy sweet pudding/custard type stuff inside them, Mmmm Mmmm good. ;)