Picked this up on another forum. Seems like 30 days goes down to 15 if you arrive from local country, but 90day rule has gone!
The officially translated new rules aren't up on the website yet.
However, a chap we know has done us an initial translation...
"A person holding a passport or other paper instead of a passport that has a citizenship that the Minister of State decreed in agreement with the Board of Ministers to let come into the Kingdom for a temporary period in order to tour according to the law and ordinances methodology and conditions of examination as "exempt" and to change the type of examination giving a stamp (year of) 2545 (day of) 16 of August (year of) 2545 Article 13)3) gives permission to enter the Kingom many times with a permision to stay in the Kingdom each time not more than 30 days counting from the day of entry into the Kingdom except that for an entry into the Kingdom by way of entry from a neighboring country the permission granted to stay in the Kingdom each time will not exceed 15 day counting from the day of entry into the Kingdom."
The 90 day in 6 month limit is no longer mentioned which is great. They only introduced that particular rule early last year and it's been nothing but hassle for their own immigration people because they had to sift through date stamps in cluttered passports and try to count up the total number of days a person spent in the country.
Those 90 days were counted on a cumulative basis, so whereas you were stamped in for 30 days, if you left again after, say, 4 days you did not lose the other 26 days. They would be held over, unlike when you leave having entered on a tourist visa where you lost any of your unused 60 days.