My application for a "non immigrant "0" visa for 3 months" was approved AFTER I entered Thailand from Germany.
 Can I stay in Thailand for 3 months without further ado or do I have to leave and re-enter Laos, for example?
 Please also describe small things I am inexperienced in visa matters.

You'll have to leave and reenter Thailand. 

34 minutes ago, ChristianP said:

Thailand from Germany.
 Can I stay in Thailand for 3 months without further ado or do I have to leave and re-enter Laos, for example?

You have obtained a non O in Thailand.

That gives you a 90 day stay.

How long do you wish to stay in Thailand.

Also was your non O based on retirement or marriage etc

 

 

4 minutes ago, DrJack54 said:

You have obtained a non O in Thailand.

That gives you a 90 day stay.

How long do you wish to stay in Thailand.

 

 

I think he has received the approval by email after he had already arrived.

This is an interesting situation. I assume he entered Thailand with a visa exempt and then got his approval letter for Non-O in the email. May be the best course of action will be to go to an immigration office and find out if it possible to convert the exempt entry to an Non-O or not. If not, how about leaving the country and renter with the e-visa for full 90-day permission to stay.

18 minutes ago, DrJack54 said:

You have obtained a non O in Thailand.

That gives you a 90 day stay.

How long do you wish to stay in Thailand.

Also was your non O based on retirement or marriage etc

 

 

He said that he got his approval after entering the country, That, makes one think he entered om exempt. Something that makes him need to go outside the country to enter again and activate.

9 hours ago, Upnotover said:

I think he has received the approval by email after he had already arrived.

Correct ...I didn't read it carefully.

Assume the OP entered visa exempt.

He will need to exit and reenter (at some point) to activate his non O.

He would need to check if this is 100% ok with a land border exit and reentry. 

 

Should have applied for visa earlier, it only takes 3-5 working days. 

3 hours ago, kelboy said:

Should have applied for visa earlier, it only takes 3-5 working days. 

that may not have suited him at the time,  perhaps?

3 hours ago, kelboy said:

Should have applied for visa earlier, it only takes 3-5 working days. 

Fake news. MUC and FRA are taking 15 working days or more currently.

Confused as to what O/P has done.

I entered Thailand on visa exempt and went to local I/O and changed this to Non Imm O.  Non IM O was stamped in my passport at I/O and I was told that I could do a Retirement extension in the last month of this visa.  Not required to leave Thailand to get this isa an assume it is valid for 90 days.;  that is what is stamped in my passport.

Now waiting out the 60+ days until I can do the Retirement extension.  Told by I/O when visa issued that no problems, just had to get all the stuff for retirement visa.

.

 

40 minutes ago, Robin said:

Confused as to what O/P has done.

He applied for non-o visa online to the Thai embassy. They issue a e visa that is emailed to the applicant. 

He did not get the email until he arrived here.

4 minutes ago, ubonjoe said:

He applied for non-o visa online to the Thai embassy. They issue a e visa that is emailed to the applicant. 

He did not get the email until he arrived here.

uj..would there be any issue for the OP to exit via land border and reenter via land with  his non O ? 

13 minutes ago, DrJack54 said:

uj..would there be any issue for the OP to exit via land border and reenter via land with  his non O ? 

I am not sure it would be possible and of course it could depend upon the crossing they used.

Most reports of doing it are from people that have done it by air.