Thailand was invaded by Japan in 1941, and of course the Bridge over the River Kwai, where Japan constructed a railway to Myanmar using POW forced labour, is in Thailand.
Invasion, five (5) hours of fighting, ceasefire, a few days that could be called occupation I guess, after that alliance that allowed Japan to operate in Thailand and build railways among other things, but wasn't formally an occupation. Dunno, I'd still put it on the not-occupied list.
Jerry my man, Thailand wasn't occupied. While Japanese troops marched through Thailand and Myanmar to get to Malaysia, occupy is way too strict of a term to use to describe their action.