Do I need to reapply for my DTV if I've lost my passport and received a new one in Thailand?

You've either lost it or you havent 🤷🏻

In German passports the past passport numbers are noted but idk about others and id expect them to just move the visa over but I would deal with the embassy who issued it rather then immigration first. I must say this is just how I’d do it. I’ve never been in the situation

I'm on a new passport as the old one expired.

First time I came back in on the new passport, no questions asked.

Last time, the IO asked to see my old passport after checking the new one, to "check something".

What would have happened if I did not have the old passport to show, I don't know.

Immigration has the right not to let you in, it's their call.

And it's factually easier for them to do so when your documents have inconsistent numbers.

If you can afford to apply again, honestly I would do it, for the peace of mind. Granted it sucks to pay again... :(

Best of luck.

a JOKE to read that DTV holders explain that if you loose your passport, you also lost your e-mail account, a printer and above all The Royal Thai Police Immigration Database lost your fingerprints, your facial recognition, your name, dob, address, nationality, date of entry, visa used and some other details.

Do as normal people do.

Go to Police, make a report of lost passport

Go to your Embassy and apply for NEW passport.

Once issued go to Immigration to get a NEW entry stamp based on the stamp you had in your old passport, YES , that information is in their database.

They find that information, using your facial recognition, your fingerprints, your dob, your name, your nationallity, your visa used on entry and some other passport details.

In most cases, you would not need to apply for a new DTV simply because your passport was lost and replaced. If your DTV remains valid, the usual process is to obtain a new passport and then contact Thai Immigration or the Thai embassy/consulate that issued the visa to determine how your visa can be linked, transferred, or otherwise recognized in the new passport.

Because procedures for the Destination Thailand Visa (DTV) can change and may depend on how the visa was issued (e-Visa or otherwise), you should confirm the current requirements directly with Thai Immigration or the issuing Thai embassy/consulate before making any travel plans.

I had to reapply

I asked for this question here because I lost my passport in Thailand, past May . Some answers to my question was that I don't need to apply again for DTV, but my new passport has a different number. For not to stay at risk, I asked the Thai Embassy in Madrid for this situation, and they answered to me: I need to apply again for DTV. And now I'm in this process.

Difficult to know if you have lost it or not?

Yes and stay out of Thailand until your visa is approved