Khao Lak

Khao Lak beach
photo by flickr user Inchka

Khao Lak is a resort town about 100km north of Phuket with beautiful long beaches and starting point for trips to Similan Islands.

The Similan Islands, about 50km offshore from Khao Lak, is an archipelago of nine island with amazing beaches and diving opportunities.

Wikitravel says:

Khao Lak (เขาหลัก) is a resort town in Phang Nga province on the western Andaman Sea coastline of southern Thailand, about 100 km north of Phuket Town. When the disastrous tsunami of 2004 struck South Asia, Khao Lak was the hardest-hit area in Thailand with over 4000 fatalities. It has since made an impressive recovery despite many hardships along the way, and is once again a popular tourist destination. Khao Lak mainly caters to families and those looking for R&R - party people prefer Phuket.

Wikipedia says:
Khao Lak (Thai: เขาหลัก) is a seaside resort in Thailand, located 80 km north of Phuket International Airport in Takua Pa district, Phang Nga province and popular as a departure point for liveaboard scuba diving trips to the Similan Islands. The pristine coastline is synonymous with beauty. Nearby rubber and palm plantations dot the coastal region and most nearby inland areas. The major national Highway 4 runs north and south and mostly parallel to the coastline. Khao Lak is a thriving tourist destination for backpackers, up-scale tourists, adventure tourists and seasoned scuba enthusiasts. Local peoples are mostly Thai often with some Chinese ancestry. The diversity of ethnic groups and cultural influences within and surrounding Khao Lak makes this region rich in agricultural, fishing and dry good products. Tourism is Khao Lak's revenue generating entity, becoming Thailand's most popular jumping-off point for the world renowned Similan Islands. ... read more