Embassy legalisation for use in Thailand
Consular attestation applies to this corridor, so plan for it from the outset. The sequence never varies: notarisation or certification where the paper is a private one, then legalization by an Italian authority, then attestation by the destination's mission here in Italy. To legalize documents for Thailand each of those marks has to be present, in that order, on the same physical file.
What the Italian stage proves
An Italian authority is not confirming that your paper is true. It is confirming that the person who signed it held the office they claimed and that the signature matches the specimen on file. That is a narrow job, and it is why a photocopy with no live signature is refused at the counter. The Prefettura handles public officials; the Procura della Repubblica handles notaries and the courts.
The consular stage for Thailand
The mission adds the mark a Thai office is actually looking for. An embassy attestation for Thailand confirms the Italian legalization, so the mission needs the Italian mark to be there and to be legible before it will act. It sets a consular fee of its own, and the stage it runs is the slowest link in the chain by some distance, which is where a tight deadline usually goes wrong.
Cost and timing for this route
The Italian charge is the €16 tax stamp on each paper, and the consular charge is whatever the mission asks. Standard turnaround for the full run is 10–15 business days, with an express option at 3–5 business days. Document legalization for Thailand is therefore a two-week job in the ordinary case, and a one-week job when you pay for pace and everything arrives in order.
What sends a Padua file back to the start
Three habits cost people the most time. Handing over a copy instead of the signed original leaves the Italian desk with nothing to match. Choosing the wrong first desk wastes a full leg, since neither office forwards a file to the other. Adding a translation after the marks are on means the new page is covered by nothing, and the bundle has to run the whole chain again from Padua. Run in the right order, an embassy legalization for Thailand from Padua needs one visit to each desk and no more.