Do you need a Visa for Switzerland and Monaco?

As in all visa questions, it depends on your nationality.

Both Switzerland and Monaco are part of the Schengen agreement area, so if you do need a visa, it would be a Schengen visa, which would be valid for both countries.

The only way in or out of Monaco is via France, or if you own a boat. France is also part of Schengen, so the same Schengen visa would also be valid.