If I understood right, with a non imigrant visa for one year and multiple entries I need to do go in and out every 3 month. But what will be happend, if I go to KL and come back without passing the imigration of Malaysia? I mean, airplain, only transit and back?
TLDR : Answer Summary
With a multiple-entry Non-Immigrant visa for Thailand, you must leave the country every 90 days. It's debated whether it's necessary to stamp in and out of Malaysia during transit. Some users suggest that keeping both boarding passes is sufficient to re-enter Thailand without breaking the visa rules, while others recommend getting stamped in and out for smooth re-entry.