BEST BEACH SPOTS in THAILAND by ARIYA HAMA : The definitive NOMAD travel guide to Kohs and Islands of Thailand
  Dreaming of a beautiful swim? Lifelong resident of Bangkok, contributing editor, Ariya Hama, shares the best beaches and islands in Thailand with NOMAD-CHIC.
“Beach spots are my favorite topic! I’m off to Koh Phayam in Ranong, Southern Thailand for the New Year. I’ve been going back there whenever I get a chance. It’s still pretty undeveloped and quiet. 
April 13th is Thai New Year - a national holiday through April 16th. Thailand celebrates New Year’s with water fights (Songkran). Be prepared to get wet. Hotels may be full as tourists arrive for Songkran. Bangkok businesses (restaurants and shops) close for the New Year and the city is relatively empty and quiet. Domestic transportation is almost fully booked because locals leave Bangkok for vacation.
If you want luxury, Phuket, Krabi and Samui are your best bets, with regular flights from Bangkok and lots of posh resorts. In Phuket stay at Point Yamu or Naka. The hotels are in their soft (opening) stages and the prices are relatively low for Phuket luxe.The Naka private island is ultra chic. Mom Tri’s Villa Royale has great food, a semi-private beach on a cove, saltwater pools, and a spa. Diana stayed there once. It’s an oldie but goldie. Koh Phi-Phi has become too commercial. Take a day trip from Phuket, but there’s no need to stay overnight. In Koh Samui, the Six Senses Resort is beautiful. I also stay at Kulay-pun (but they’ve changed management recently). There are lots of luxury resorts on the island. There used to be endless coconut plantations and coral reefs, but everything has been ruined by overdevelopment. I’ve been to Krabi once - a decade ago- and all the nice hotels are in Ao Nang Bay. I stayed at the Rayavadee- accessible by boat only. It was surrounded by limestone cliffs, had a private beach, lots of wild life, and a really nice restaurant in a cave.
For pristine beaches, diving  and snorkeling, Koh Similan and Koh Surin in Phan-nga province are beautiful. They are part of Thailand’s National Parks. If you are really into nature, I’d recommend these! 
Koh Samet in Rayong province is a favorite getaway for city locals. The drive is a few hours from Bangkok- with a  20-minute speedboat ride to the actual island. I stay at Tubtim resort, which has a decent beach and excellent food. Next to the beach is Ao Nuan, a very quiet beach with a single, basic bungalow. The sea isn’t as beautiful as on the other islands but it’s an easy, long weekend beside the ocean.
If you have a lot of time I’d recommend traveling further south to Trang Province (Koh Ngai, Koh Muk, Koh Kradan) and Satun province (Koh Lipe). Koh Muke is a five-hour drive from Bangkok, followed by a 40-minute speedboat. I stay at Coco Cape. The jetty leads to a crystal clear sea and the accommodation range is huge- between $15 a night to $250 a night for a room at the resort. But the food is pretty awful.
For low-key islands on a mid budget, with decent beaches and quiet, safe lodging, I recommend Koh Phayam in Ranong. Fly via Nok Air or take a bus. I usually take a night bus there and fly back to Bangkok. The bungalows are very basic with a fan and a cold shower, but the rate is $16 a night. Koh Mak in Trat is also good. 
If you only have a few days, head to Hua-Hin, a two-hour drive from Bangkok. It’s an old resort town where you’ll find a lot of nice hotels and restaurants. The beach is pretty, but the sea is not the turquoise blue found on the  islands. The best places to stay are Barai, Putahracsa resort, Hotel de la Paix, Chive-Som and Anantara. Charter a cab, although regular buses and minivans leave from Bangkok. Or you can take a slow train there.
Koh Tao in the Gulf of Thailand is easy to get to. You can stay in luxury accommodations, visit peaceful beaches with good snorkeling or go to backpacker filled party beaches. Try a  hotel on Shark Bay- you will bump into sharks in the water, but they are friendly.
Phan-ngan is a tourist trap filled with backpackers heading for full moon/ half-moon/ black moon parties. Not much there except drunk revelers. Koh Chang in Trat and Koh Lanta in Krabi are also mentioned in the guidebooks but the sand is quite coarse and yellowish- therefore not too nice if you want comfy, soft, sandy beach to lie on- and the water is a little dirty.”

~Ariya Hama
Excerpts from an email between contributing editor Ariya Hama and Awaveawake’s Jaclyn Hodes, currently traveling in Asia.