When you want to enjoy and relax on the beach in South Eastern Thailand mainland, forget about Pattaya which is too crowded. Rim Phae Beach or Hat Rim Phae will be the perfect choice.
Away from bustling Bangkok and Pattaya, Rim Phae Beach provides long sandy beach, several hotels/villas/cottages, and great view to Koh Samet and 5 other smaller islands in the gulf of Thailand.
There are also several local/seafood restaurants should you need something to eat.
And for the activities, you can do swimming, riding banana boat, or rent a boat to go to small islands for skin/scuba diving.
Fondest memory: I have to tell you this particular story when I was here. It was a really nice day when we arrived and my mate, Pete, suggested we go squiding sometime midnite on someone's boat...whoever, you know...neone that can take us out to sea for some fun. So Pete went around asking people if we could join them on their fishing trip but all of them refused! Well, apparantly, there were pretty big waves that night and there was a storm out in sea. A fisherman who had ventured out was missing and they still couldn't find him. So we sighed...boo hoo! The next day, they found him! He was dead though... : (