Probably your go-to noodle spot on the east of the I-15
Most of the ramen joints in Vegas are located west of the I-15, in and around the Chinatown and Spring Mountain area. Over on the east side there are still options, but pickings are slim. Shoku Ramenya comes from the same folks who own the Asian-fusion Bachi Burger next door, and is located in a ramen no-man's-land on East Windmill between one entrance to the 215 and another. It's not THE bestest-best ramen in Vegas -- though an Uber driver once told me he used to come to town from LA just for this ramen, so YMMV -- but when you're on the east side and don't feel like driving half an hour for a hot bowl on noodle soup, this'll do ya just fine. Try the tonkotsu black garlic ramen for something a little different.
Tropicana East Shopping Center
A mecca off the Strip well worth the pilgrimage
It's a ways off the Strip in one of Las Vegas's many, many, many boring strip malls (we do not so much have neighborhoods here as we do collections of strip malls with names) with its closest landmark of significance being UNLV, but rest assured that Fukumimi Ramen is one of Las Vegas ramen devotees' favorite spots, arguably more so than some of the better-known joints on Spring Mountain. Get the spicy tonkotsu ramen with thick noodles and top it with chashu (pork belly) and nitamago (seasoned soft-boiled egg), or the signature Fukumimi Ramen with thin noodles in salty broth with extra chashu and seaweed.
Spring Mountain Road
A sushi bar and ramen joint known for its vegetarian options
Despite a name that makes it difficult to accurately hashtag your Instagram post, Go!ku is another favored spot among the ramen-slurping elite. Some fun choices include the "Vegas-style miso" with pork broth, pork chashu, ground pork, half-boiled egg, menma, seaweed, baby spinach, bean sprout, and green onion. This is also one of the few ramen joints that really puts a lot of effort and emphasis on their vegetarian and vegan ramen options. FYI, "J-wraps" are sushi rolls.
One of the few spots that provides complimentary hair ties
This brand-new spot on Spring Mountain (not even open three months yet) is already getting rave reviews from local ramenistas. Billing itself as "more" of a "Japanese-style" ramen house (as opposed to…?), you sit at a long bar (there are no tables) and fill out a form selecting your various ramen options. The kitchen is open, and everything is made here from scratch without MSG. (That means it might not be as noticeably salty as other places, which may or may not matter to you.) They also provide hair ties to further facilitate your slurping, which is both hilarious and incredibly practical. The chashu is the real standout here, so start with the Chashu Don.
Late-night ramen joint where you're welcome to sit seiza-style
Izakaya's happy hour is from 10pm to close, which is 2 or 3am depending on the day, so that should give you a good idea of the kind of crowd you're going to find here. But it's not all weekend warrior party animals; you'll also spot young student types burning the midnight oil and plenty of families here. It honestly feels like the ramen joints you'll find all throughout Toronto (my closest metric of comparison for what I think an actual ramen joint in actual Japan might look like). Despite being located in yet another soulless strip mall, the interior design is actually quite fetch. There's also a communal table for large parties with seiza-style seating. The menu is extensive, with ramen being only one small part. Here, your choices are shio, shoyu, or miso ramen, all spicy and all made with a chicken broth base. They also have an excellent booze selection, if that is a concern of yours.
Probably the best-known name in ramen in Vegas
When Las Vegans talk about ramen, they talk about Monta ramen. In this intimate, wood-paneled space, you can choose from tonkotsu, shoyu, tonkotsu-shoyu, and miso ramen. Cold noodle ramen is also an option. This place is a great spot for ramen noobs to be introduced to the different styles of ramen, as the menu gives thorough descriptions of what each style is, what it's made from, and the flavor profile for each. In most other places, you kind of just have to know what you're ordering. A second location in Henderson has since closed due to issues of mandatory construction, but they are looking to relocate it somewhere else.
Authentic ramen imported from across the ocean
Most restaurants in Vegas are imports from elsewhere -- LA and New York, mostly. Ramen Sora is also an import, but this one hails all the way from Sapporo, Hokkaido -- the northernmost main Japanese island. Helmed by Japanese chefs Tomio Takada and Yoshinari Ichise, the ramen can be quite a bit more unique than at other places. Try the corn butter ramen or the very, very spicy Screaming For Vengeance ramen for further proof of that.
Just off Spring Mountain Road
The place to get your tsukemen (dipping-style) fix
You will either like Ramen Tatsu's deconstructed ramen presentation, or you will not. The specialty here is "tsukemen ramen," which basically means the broth is dense (for dipping) and served separately from the extra-thick chewy noodles and toppings. If you're not into that, no worries, the menu is full of all the standard ramen options as well, and if you like your ramen real spicy, they even have a tonkotsu broth made with habanero sauce. They've also got a few non-standard options for toppings, like garlic chips, kimchi, and kikurage (wood ear mushrooms).
Flamingo and Decatur
This fast-casual joint still makes pretty damn good ramen
JINYA is actually a ramen bar chain with locations throughout the US and Canada -- basically trying to be the Chipotle of ramen -- but it's still a favorite in Las Vegas. "Have it your way" customers will appreciate the level of customization available, although that number of options can be a little overwhelming. Options include a variety of tonkotsu and chicken broth ramens, and there are also vegetarian and vegan options. If you’re more of a ramen traditionalist, you can stick with one of the more standard flavors, but they've also got unique choices like spicy umami miso, and, shall we say, more "marketable" choices, like wonton chicken (ramen with dumplings), and chef's specials like karaage chicken (ramen with fried chicken).
On Charleston across from the CSN campus
The ultimate ramen joint for students who need to refuel
A ramen bar geared to the student crowd conveniently located literally across the street from the College of Southern Nevada's Charleston campus, Moko is a casual but modern and stylish space open for lunch and dinner. Menu items include a Meat Lovers ramen -- tonkotsu broth with chicken, beef, and pork bulgogi; spam; chashu; kurobuta sausage; and chicken katsu -- and a Veggie Lovers option with miso broth, tofu, cabbage, spinach, corn, kimchi, bean sprouts, and green onion. The non-ramen rest of the menu is a bit of a grab bag of Japanese and Korean items, but they seem to have a good grasp of their college student demographic and the dinner menu is surprisingly sophisticated for being a "ramen joint."
This neighborhood finally gets its very own ramen joint
It's the first (and as of right now, only) ramen house in the northwest 'hood of Centennial, and that's one of its biggest selling points. Ichi is definitely solid, with a menu of standard ramen dishes that stacks up to most other ramen joints in the Las Vegas Valley, plus a few non-standard options like tomato seafood, black garlic, curry, and vegetarian ramen. Ichi prides itself on using fresh noodles, authentic ingredients, plus long-simmering broth varieties that each take three full days to cook.
The other Japanese spot in Centennial, with plenty of options
Ichi Ramen House might still be Centennial's only ramen-specific restaurant, but Centennial has also recently acquired its very own Japanese restaurant, and it is legit. Being a Japanese restaurant and naming yourself "Umami" is a bold move, but the name is justified. Ramen is just one of many things on the menu, all of which is excellent. Centennial is slowly transforming itself from a chain-centric suburban sprawl wasteland to a destination actually worth seeking out!
A divisive late-night joint with tons of options
Another well-known late-night ramen joint, Ichiza has its die-hard devotees as well as its die-hard detractors. Love it or hate it (and probably it's one or the other), Ichiza has a massive menu with a LOT of options, of which ramen is a small, small portion. Definitely something for everyone here, at least, and they usually have a pretty extensive selection of specials, too.
A new local chain that's already distinguished itself
With one location on the west side in Spring Valley and another over on the east side in Henderson, local noodle chain Ohjah just came onto the scene last December and is already a cult favorite around town. Get the Ohjah House Ramen with oxtail, beef, egg, bean sprouts, seaweed, and wood ear mushrooms -- it's their specialty and this is one of the few places around town where you can get oxtail in your ramen.
On the Strip
An award-winning full Japanese menu, right on the Strip
Here's an option conveniently surrounded by all the casinos you might want to hit up anyway if you're spending a weekend in Vegas. When the Paris Hotel & Casino began expanding their restaurant portfolio to include more Asian options, they did not half-ass it. Sekushi is an excellent option for a wide variety of Japanese items -- ramen, sushi, and otherwise -- in a stylish space to boot. You'll have to pony up for on-the-Strip prices, of course, but it won't do you wrong.
On the Strip
The sister restaurant of a Michelin-recommended SF shop
If you're on the Strip and have a ramen itch you need to scratch, this place is also totally acceptable. It's actually a satellite of the Ramen Katana-ya Group in San Francisco -- which earned spots in the Michelin Guide for three years running. At the Vegas location, try the lemon shio ramen, and get a sushi burrito while you're there, because YOLO.