Mortgage loans from foreign banks at lower interest rates I had a thought - what if I live in a relatively poor country like let's say Russia and I would like to buy a house. In order to do that, I need to take a mortgage loan. In Russia however, interest rates are pretty high, lets say the best offer from a bank is 15 % annually. That's a lot but due to high interest rates, unlike in rich EU countries, the housing prices relative to income are not that high.

What does stop me from taking a loan from a bank in a rich EU-country to build or buy a house in a poor country like Russia, while having EU-level interest rates below 3% instead of the Russian 15%?
The low interest rate will be in a different currency. If your domestic currency falls in value, the value of the mortgage in terms of the domestic currency goes up.

Entities borrowing in a foreign currency and then running into difficulties is a standard features of financial crises over history.