Naklua's fishing port sits at the northern edge of Pattaya proper, mostly invisible to tourists. The boats come in around 04:00; the port is at its busiest from about 05:30 to 07:30; by 09:00, what's not been bought has been packed in ice and trucked out.
What you can buy directly from the port — if you're willing to be there at the right hour — is a different category of fresh than what arrives at most Pattaya restaurants. The good seafood restaurants in the surrounding three-kilometer radius source from this port; some of them buy at 06:00 daily.
If you're trying to learn the difference between fresh and 'fresh,' walk through the port one morning. Look at how the eyes of the fish change between the boats and the wholesale stalls. Look at how the prawns sit on the ice. Then go eat seafood that evening at a restaurant that buys here, and compare it to one that doesn't.
This is the closest most Pattaya residents will ever come to terroir.