What are the major differences between the Gulf of Thailand coast and the Indian Ocean coast? Which is better for a quiet pampered honeymoon?

When are you going?

Either May or September

Gulf coast then will be better. Try the Evason at Pranburi, just south of Hua Hin, fabulous villas with their own pools, also you don't have to fly, you just go by car from Bangkok in about 3 hours. Or try Koh Samui.

East coast has more of a party atnmoshere. West coast is better for a quiet time on the beach. Both are good. Keep an eye on where the best weather is to get the best of it. FYI a taxi from Krabi (on the west coast) to Surat Thani (east coast port for Koh Samui) is only $30 and takes three hours max. You can do both with ease.