Unlike in other European countries, the information accessibility in Russia is quite limited, I recommend you to do a little research before going. Here I will share with you what I have noticed after my own trips in Sep. 2016 (to the Far East) and in Oct. 2016 (to St. Petersburg and Moscow). Hope it will help a bit.

– Firstly, don’t expect Russian to speak English. They mostly don’t, even in big cities like St. Petersburg or Moscow. So you’ll need even more proper preparation.

– You should prepare an amount of Russian rubles before going. There is no currency exchange in Khabarovsk International Airport (yes, the airport is surprisingly small). And the currency exchange in Vladivostok International Airport closes before 6pm (I don’t know the exact time, may be 5:30pm, last time I went there at around 6pm and they already closed). If you want good exchange rate, I recommend exchanging an amount of 2000-3000 rubles/person for the first day only (for taxi, lodging, food and unexpected expenses) then you can exchange more at some banks inside the city.

– Google map is useless.. It can show you your current location, but cannot show you how to reach a destination (except going on foot). Below are some useful applications you may need in Russia:

For taxi: Yandex Taxi:   IOS   Android
Maxim:   IOS   Android
You can use both, for reference. Sometimes the price of Yandex is cheaper than Maxim, and vice versa. However, you can reserve taxi in advance (for example, book a taxi for tomorrow) using Maxim, but you can’t with Yandex.

For city’s maps: Yandex Maps:   IOS   Android
You can download maps to use them offline.
The map will show you your current location, some famous attractions/spots, and how to reach the destinations by car, bus/train, walk. But note that you can see the transport options only within Russia. I tried to use it in Japan but saw only one option – by car.

Real-time Transport Track: Yandex Transport:   IOS   Android
Although Yandex Maps can show you many transport options, you will not know when your bus will come. With this Yandex Transport, you can see the location of your bus in real-time. And don’t forget to check the type of the bus you’re waiting, if it’s mini bus, normally the service will stop at 9pm, and the big bus’s service will stop at 11pm (as a Russian told me when I was waiting for a mini bus at 10:30pm).

– Apparently there’s wifi in many cafes and restaurants and some public places like museums, but I really recommend buying a SIM card to use anytime you need. There are 5 operators: MTS, Megafon, Beeline, Tele2 and Yota. Last time I used MTS because the officer at the airport recommended it. I paid 400 rubles (~6$) and got relatively fast wifi service for all 6 days staying there. For more information please visit Wikia.

– One last very-important-thing for Vietnamese. Apparently, the immigration check has got really strict with every Vietnamese passport holder, regardless of the country you’re living in. So, be sure to prepare every paper that can confirm your purpose of visiting Russia: invitation letter, passport, hotel/train/bus reservations, contacts in Russia… And give yourself more time on your first day of arrival, the inspection may take 1-2 hours and you don’t want to miss any plan just because of it.

There may be other things that I cannot remember right now, so if you have any questions, feel free to ask me.