There are decent beaches around Pattaya. None of them are IN Pattaya
From best to worst:
Koh Larn (very nice, not as good as Phuket but still very nice), Back side beaches facing away from Pattaya are the best, take Twaen Beach Ferry (about 30baht and 45minutes )
Koh Larn, Front side facing Pattaya, take Naban Ferry (about 30baht and 35minutes), There is a 7/11 right at the dock and the main town with restaurants, guest houses etc. The nearest beach (I think) is also my favorite on the island. Naul (Monkey) beach. Feels secluded, lots of coconut trees, semi wild monkeys in trees, not bad snorkeling (you can rent it there). You may need to rent a scooter to get out there. No sure if there are guys who will take you there and pick you up or not.
http://kohlarn.com/schedule.htm
http://www.kohlarn.com/beach.htm
Sunset Beach (?), Take Sukhumvit for about 20 minutes to the next town past Jomtien which is called Na Chom. It's just past that, look for a sign. Nothing special other than nice fine white (ish) sand. Not much around there other than the beach.
Bang Sare, the next town after Na Chom and maybe another 20minutes. Quiet fishing town with a nice long crescent beach and views of Jomtien off in the distance. It's kind of a simple red clay sand type beach that is nothing special but combined with being in a small fishing town atmosphere with a few places to eat makes it a nice day trip.
The beach between Jomtien and Pattaya (Asia Beach?) near Cabbages and Condoms restaurant. Better than Jomtien because not as busy, no traffic etc. Go towards Jomtien and at the top of the hill head towards the water. Look for signs. Keep going till you find the parking lot.
North Jomtien Beach. Where the Road to Jomtien turns and goes along the beach take the pedestrian only path along the beach in the other direction walking back towards Pattaya.
South Jomtien Beach. The long one everyone is familiar with that the baht busses go up and down.
Naklua. Go towards North Pattaya and after the roundabout look for a sign that points towards the water. Not much of a beach but it has big rocks and stuff to crawl around on so kind of interesting.
Pattaya beach. The one everyone is familar with and leads them to think there are no nice beaches anywhere.