Recently we spent a long weekend on Koh Lanta in southern Thailand. From KL it is a short (and cheap on Air Asia) flight to Krabi and then a transfer to the island itself. Koh Lanta bills itself as a less party-oriented than other nearby resort areas (like Koh Phi Phi). This is definitely a relative measure, as a drive along the island’s main beaches showed packed tourist shops, bars and hotels. Although, the further south down the island we went the less touristy it became.
Our hotel, LaLanta Hideaway, is the most southerly on the island and backs onto a national park. Thus it is quiet and remote from the tourist strip - which is exactly what we wanted. The weekend was spent lazing around the hotel and the beach it backed onto. We walked, swam, kayaked, had a massage, and ate. A very relaxing trip.
The only downside is the transfer from Krabi airport to the hotel. It took 2 hours 20 minutes on the way out and 3 and a half hours on the way back (when we got caught in traffic). Compare this to the flight time of 1 hour 30 minutes.