Jona (German pronunciation: [ˈjoːna]) is a former municipality and since January 2007 part of the municipality of Rapperswil-Jona in the Wahlkreis (constituency) of See-Gaster in the Canton of St. Gallen in Switzerland. Before the merger with Rapperswil, the former municipality of Jona comprised the villages of Jona, Bollingen , Busskirch , Curtiberg, Kempraten -Lenggis, and Wagen.

The former municipality of Jona extended from the eastern shore of the main part of Lake Zürich (Kempraten) to the northern shore of Obersee, the upper or eastern division of Lake Zurich (Bollingen, Busskirch). The former village of Jona is located on the River Jona, which flows into the Obersee.

The River Jona flows through the former Jona municipality in the Obersee (upper Lake Zürich).