Transport: I used Omio to book transport around Europe and it’s great to have all my tickets in one place. There is train as well but I have never taken them.
Currency: Euros, Latvia has joined the euro zone in 2014. Card payments are widely accepted as well.
Sim Card: Many sim cards are valid for entire Europe
Handy Apps: Bolt taxi app is good to use.
Language: Lettish is the official language, but people in Latvia speak good English.