You will rarely find a bad meal in Thailand, but after weeks of plastic tablecloths and street food I found this place to be a real treat – Time for Lime, on Klong Dao beach. From memory I think my partner and I may have spent around £20 which was well beyond the £6 that we normally spent on dinner, but well worth it – modern thai mains and desserts and great cocktails. Koh Lanta turns on an amazing sunset as well so try to get there a littler earlier and grab a seat on the top floor balcony. They also host a cooking school if that sort of thing grabs you.
Another alternative if you are camped out at Phra Ae Beach is a little place at the southern end of the beach – part of Lanta Sanctuary I think. Causal mats and pillows set up on platform at sands edge and food is around the standard £6-7 for 2. Can’t remember much about the mains, but we still talk about the banana pancakes!!! over 10 years ago
Time for Lime. They change their menu daily, but everything they make is awesome. And they're a non-profit - the owner also founded the island's animal shelter. The cooking school at Time for Lime is great, too!
I'd also recommend Don's and Bamboo. Good, cheap, and good service. about 6 years ago