It is by far one of the most essential things that you'll need to do upon your arrival. Blessed are those who pre-paid some (grossly overpriced) international data package with their operator back home, this article is not for them (unless they want to find out how much they could've saved by buying internet here). This article is for everyone else who still has no idea of how to make sure that you always stay online once you've reached Russia. Here's some advise for you:
Know before you buy
First and foremost, every train station and airport in Moscow has free Wi-Fi access. So if you just realized your imminent internet needs right before the take-off, no need to try to memorize the rest of this article, as you'll be able safely re-connect to the Web once you land.
Second, internet access in Russia, wired or wireless, portable or stationary, limited or not is absolutely undoubtedly one of the cheapest on Earth! Everything you book buy, book, look for during your trip will inevitably be connected to the internet in one way or another. So remember, considering the price that the country asks for its Russian megabytes, there's absolutely NO excuse for you not to buy a local SIM-card if you don't have any other alternatives. If it becomes useful at least ones during your trip, you'll already break even on your investment. Current most affordable options start with 299 RUB for 3 GB of mobile data.
Third, there are three biggest mobile operators in this city. Beeline, Megafon and MTS. In terms of their coverage and its quality, there are always plenty of conflicting studies and reports on the internet each trying to promote the one who paid them most. But the truth is, if you're not trying to venture too far outside of the city, they are nearly identical. All provide good, fairly stable, high-speed 4G LTE connection with a serviceable reception indoors. There might be slight differences when it comes to reception on different metro stops (your internet usually works there as well). But ultimately, for you as a tourist who came here for a week there's absolutely no need to spend the whole day trying to pick the best one. Price-wise they are pretty similar too.
Exception is the fourth operator that appeared on the Moscow market very recently - Tele2. Since it just popped up here, it might potentially suffer from more technical glitches and coverage gaps (especially in the metro) than the tried and true ones. So better stick to the main three.
I myself use MTS.
Fourth, there are 3 major mobile phone retail chains that officially distribute SIM-cards of the aforementioned operators: Evroset, Svyaznoy and MTS. There used to be only two, but MTS operator at some point simply said that it's time for it to open its own theme park with blackjack and stuff and opened a very sizable chain of stores across the country. As a response to growing competition other two chains stopped selling MTS products. So now it first two shops you can find only Beeline and Megafon, and in MTS stores you can find only MTS.
Here are their typical logos for you to visually identify them:
In big crowded places like shopping malls and airports you can also find standalone stalls selling just SIM-cards of either one of those operators individually. Here's how they might look like:
Now all you need to do is to take a look around and find any one of them nearby, go there and buy your card.
Where and how to find
If you appreciate your nerves at all, better do it right in the airport. Just take a walk across the waiting area. No matter where you land, at least one of those shops or stalls should be somewhere near right after you clear the customs. If you're already in the city, then just go outside and walk literally in any direction until you see one of them. There are thousands of them out there.
It's better to do it in the airport though not only because it'll make your life immediately so much easier, but also because you chances of finding a person who understands you in an airport are much better than in the city. In the city people might not understand you even in McDonald's when you try to order a cheeseburger. Getting it here should definitely smooth out the process.
Now, if your conversation has hit the snag anyway, don't despair. There not that many reasons of why could you come to the shop that sells SIM-cards and talk to the guy that sells them. Sooner or later he'll figure it out. But to make it faster, add some visual aid. Show up you phone and say, "SIM". Avoid long sentences, just SIM, that's it, until he starts asking you something further. If you need just data, for example, with no calls, don't say, "Just data". That might not convey the message. Say, "No calls... No calls... Internet... Internet..." And shake your head from side to side while keeping your phone next to your ear when you say that. "No calls...", practice it;)
Well, I'm obviously joking to a certain point here. Your conversation will most likely be much better and more like an actual conversation. But to completely skip the conversation part, you can just use the links below. Open them and show from the screen of your phone. The shopkeeper will know the exact plan that you want to connect to. I've tried to select here the best plans available to date (18.03.2017) from all three of the operators here.
Choose your tariff
MTS - 10Gb of data per month and 300 minutes of outgoing calls within Moscow - 500 RUB per month:
Beeline - unlimited mobile internet anywhere in Russia with no calls - 600 RUB per month
Megafon - 3Gb of mobile internet per month anywhere in Russia with no calls - 350 RUB per month
Or again, you can just talk to the guy for more options:)
Buy and make it work
After you've chosen it, he'll need your passport for 5 minutes or so, during which he will ask the address of the hotel you're staying. When he returns it to you, pay for your SIM with rubles or a bank card. Then put the SIM-card inside your phone and make sure that it works.
Now this is the last but the most important step. Some tariffs require some additional button pressing on your phone before they start working. Or it just might need 10-15 minutes for them to get going. So if you've already established some conversational understanding with your shopkeeper, just tell him to make everything work right away. Otherwise, just show him this:
"Пожалуйста, настройте так, чтобы все сразу работало".
It says, "Please, make it work right away".
If the person knows what he's doing, you won't even need to hand him your phone. However, if it comes to this, and you're not so certain about the quality of the rapport between you and your SIM-card man, just don't leave the shop until it works. That should certainly do the trick.
And... Presto! Now you should be a happy user of Russian mobile internet. Congratulations on that!