If you are travelling only in zone 11 and/or 12, you must purchase a Mobilis ticket called “ Grand Lausanne ”. This costs the same as two zones, and allows you to travel in both zones without having to worry about accidentally crossing the borders between them.
Tickets for zones 11 and 12, which cover  Greater Lausanne , cannot be purchased individually.
Zone 11 must be purchased with at least zone 12
Zone 12 must be purchased with at least one neighbouring zone.
If you aren’t travelling far, a “ Short Journey ” ticket is also available.