I'm from Denmark and I have a danish passport. My age is 37.

On holidays in Thailand I normally stay 3-4 weeks and I always get the 30 day entry stamp and no visa.

Next time the stay will be to the limit of the 30 days, and my question is: Is my next stay within the 30 day entry stamp og do I have to get a visa?

Travelling details:

Depature: 10th may 14:35 Copenhagen

Arrival : 11th may 06:00 Bangkok

Departure: 10th jun 01:20 Bangkok

Arrival : 10th jun 07:25 Copenhagen

When counting days, 11th may - 10th june is 31 days, but I will pass through passportcontrol in airport just before midnight 9th june, which then gives 30 days

Or what?

This is a more generic point about this but on more than one occasion on arriving at BKK AFTER midnight, they have stamped me in as if I actually arrived BEFORE midnight. Bummer.

You should get permission to stay til May 9, leaving 10th you are on 1 day overstay.

Don't think, however, you will have a problem passing through immigration +/- midnight 9-10th.

I've done this before with no problem, just make sure you get through immigration before midnight to be safe.

or.....if all else fails, get a visa. It is not a hard, or an expensive process. It also avoids the ' what if ' problems