What is the official date of a marriage?

You sign the book at the Amphur

<You ain't really married till you sign the book, THAT date is your anniv and official date - period. The date you wed has no bearing whatsoever>

OR

The date the ceremony is performed.

<You can marry one day or one year prior and register the date of ceremony as the official date in the registrar/book>

???

We recognise the date we had the ceremony with all family and friends as our anniversary, and to us that is when we got married. That is the date we committed to each other

For anything formal or legal though we use the certificate date that we signed and registered at the ampheur.

Same as many Thais will recognise the day they were actually born as their birthday. However, the date formally registered at the ampheur may well be different, and is the one used on official docs.

Bad enough remembering one birthday and wedding anniversary, let alone 2. Worth pretending you married royalty though, as the queen in the UK has 2 birthdays

BTW For marital status my previous employer had "married with certificate" and "married without certificate" as boxes to tick for employee benefits. Basically they were entitled to the same company benefits for family in each case, but is one of those Thai things.

T.I.T

Per above. For many Thais it is the day you perform the cermony, but that is only tradition. The law only knows the marriage you perform by signing the wedding register at the amphur, for the law and government that is the day you got married and that is what you fill in on applications and such.

A ceremony is nice, but as in many countries it does not constitute the legal requirement for a marriage.

Thank you both.