If you have Swiss citizenship, are at least 18 years of age, live in Switzerland, and are not subject to guardianship due to long-term lack of capacity of judgement (and you are not represented by a proxy designated to act on your behalf for this reason), you can vote at federal, cantonal and communal level and also launch and sign referendums and initiatives.
You do not need to register the first time you vote in a federal vote or election: you will be added to the electoral register of your commune of residence as a matter of course as soon as you fulfil the conditions for being eligible to vote.
If you are a Swiss citizen abroad, you can vote at federal level (e.g. in National Council elections). However, you must be registered with your Swiss representation abroad. You must also be registered on the electoral roll of your last commune of residence in Switzerland or, if you have never lived in Switzerland, in your place of origin.
In some cantons, Swiss citizens abroad can also vote at communal and cantonal level, e.g. in Council of States elections (one of the two chambers of parliament, which represent the cantons). For information on the voting rights of Swiss citizens abroad at cantonal and communal level, please contact the authority responsible in your canton.
Dual nationality does not affect your voting rights in elections and popular votes. Dual nationals can vote and participate in elections, unless other reasons prevent them from doing so.
Although you have to be 18 or older to vote at federal level, each canton is free to give minors voting rights at cantonal level. Currently Glarus is the only canton to allow 16- and 17-year-olds to vote on cantonal and communal issues. Citizens of Glarus cannot, however, run for government office until they are 18 or older.
Foreign nationals do not have the right to vote at federal level. However, in some cantons, they do have the right to vote in cantonal and communal ballots.