High Season: Langkawi to Koh Lipe
The easiest way from Kuala Lumpur is to fly to Langkawi. In high season daily boats connect Koh Lipe and Langkawi, the boat ride takes about 1 hour to 90 minutes, depending on the weather.
You will have to go trough immigration on both sides as this is an international border crossing.
Low Season: Hat Yai to Koh Lipe
In low season the only way to get to Koh Lipe is via Pak Bara. Daily boats to Koh Lipe run at 11.30 all year around. In Peak season there are also boats in the afternoon.
It's easy to get to Pak Bara from Hat Yai, there are both private taxi's and shared minibuses available.