Based on Etihad Airways and their partners Alitalia / Jet Airways you may currently consider to book extremly cheap return flighs from Italy (Venice, Milan, Rome) to Thailand. Roundtrip flights are now available already for €324. (Return ticket including all taxes as well as checked in luggage up to 30kgs). You may also consider to book open jaw ticket e.g. to fly to Bangkok then travel down to south and return from Phuket..
If interested in this Alitalia / Etihad Airways promotional deal you may generally find the cheapest flights when departing to Thailand till end of June 2016. All travel must be completed by 10th of July 2016. Booking is valid only till 29th of May. The easiest way to check your connection possibilities is through Skyscanner. This tool gives you quickly a rough idea which low-cost airlines are connecting your home town.
Italy (Venice, Rome, Milan) – Bangkok from €354 (directly with Etihad Airways)
Booking sample with Etihad Airways – Cheap flights from Italy to Thailand €324!. In this case you would be flying from Milan to Bangkok on 18th of June 2016. You would then fly from Thailand in Asia back to Italy on 9th of July 2016.