Which country should I list as my boarding country for the TDAC, Spain or France?

It asks for both

The flight that’s arriving in Thailand

Last flight to Thailand Simm Sima . I answered this question a few days

Country you boarded from

clear as mud ha ha ha

Here's the gig! You should list the country/city where your flight to Thailand actually departs from — your last departure point, not where you originally began your journey.

In plain terms:

If you flew Toronto → Seoul → Bangkok → Origin of flight = Seoul, South Korea

If you flew Vancouver → Tokyo → Chiang Mai → Origin of flight = Tokyo, Japan

Why Thailand does it this way

Thai Immigration cares about:

where you physically boarded the aircraft that entered Thailand

health, immigration, and routing control

airline manifest consistency

Their system matches:

TDAC entry

airline arrival manifest

immigration scan

Those always reference the last international airport before Thailand.

Summary (easy rule)

Origin of flight = the airport/country of your final leg into Thailand.

Not your home country.

Not your ticket origin.

Only the last takeoff point before Thailand.

Enter the flight going into Thailand.

It’s the equivalent to the old arrival card and the details should be where you arrive from which in your case is the layover in France so enter the details of the flight you enter Thailand on. Deep down it doesn’t matter but best to get things correct

Flight origin on your itinerary..

Where you started your journey to Thailand

Where are you getting on the plane? Spain? That's where you boarded. It's the country you are coming from.

Your last flight before arriving Thailand 🤓