Please note that while Switzerland is not included in the free roaming of the EU area, free roaming is covered in non-EU countries Norway, Iceland, and Liechtenstein.
See question 14 here at the EU website for the list of countries covered by free roaming:
https://ec.europa.eu/digital-single-market/en/faq/question-and-answers-roaming
- In which countries can I roam like at home starting on 15th of June?
In all 28 countries of the EU: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Poland, Portugal, Romania, Slovenia, Slovakia, Spain, Sweden, United Kingdom and in the countries of the European Economic Area: Iceland, Liechtenstein, Norway.
Edit to add: this came into effect on 15th of June, *2017.**