thumb|Soffioni in [[Larderello, Tuscany, Italy.]]
Soffioni (; sometimes spelt suffioni), a name applied in Italy to certain volcanic vents which emit jets of steam, generally associated with hydrogen sulfide and carbon dioxide, sometimes also with a little ammonia and marsh gas.
The soffioni are usually arranged in groups, and are best represented in the Maremma of Tuscany, where they contain a small proportion of boric acid, for which they are utilized industrially.