If you plan on staying longer than 10 days in Costa Rica I would get a local Pre-Paid Sim Card. The company with the best mobile coverage is called “Kölbi”. I used a Pre-Paid Sim Card from them for the past 5 months and never had any problems with them. It costs you around 1500CRC or 2$. For additional 4000CRC or 6$ you will get around 2 GB of mobile data. Most restaurants and stores have free Wi-Fi for you to use, but you will need your data when you want to order a taxi to the beach and back. Or use an online translator in order to break the language barrier. There is an electronics store (TecnoMundo) close to the Info Centre where you can buy all said things. The guy working there can speak English & German and can answer all your questions concerning Kölbi. Supermarkets or Minimarkets usually sell those SIM Cards as well just look out for the Kölbi sign and talk to a person working there.