What are the roaming charges for Russia (e.g., Moscow, St. Petersburg) if I use my existing EU, UK, or US mobile plan instead of eSIM ProZone?

Using your home EU, UK, or US mobile plan in Russia will almost certainly incur significant international roaming charges. Russia is not part of the EU/EEA 'roam like at home' agreement, meaning your carrier will apply their standard, often high, rates for data, calls, and texts. For example, a single MB of data could cost several dollars, leading to substantial bills even with moderate usage. eSIM ProZone offers predictable, cost-effective data packages for reliable connectivity in cities like Moscow and St. Petersburg, avoiding unexpected expenses from your primary provider.