Do i need an international driver's license in Langkawi?

Officially you need an international licence in Malaysia. You may be able to rent a bike, but as you say, if you are stopped there could be problems. The new highway across the island is not very safe on a bike. There are only a few roads on the island and not much to see off the beaten track.

Saw the worst driving in my life there. Guy on superbike going 150 holding a toddler sitting behind him with one arm. facing backwards i.e. back to back with the guy.

Lots of stray dogs on the back road out to the Craft Centre and a long and uncomfortable trip driving past the piles of rubbish at the side of the road.

Langkawi is a real flip coin. My impression was that they just try to make the most out of tourists as they can. It was also much more Islamic than I thought it would be in Cenang  Try and avoid school holidays in July as prices will go up.

Check when it is Ramadan as well as it is over part of July this  and that will affect the atmosphere as well