Why there is no jazz, and what there is instead
Pattaya is a beer town with a rock scene, and the reason it has almost no jazz is the crowd. The rooms fill with people who want to sing along, and a band that plays the room plays the songs the room knows. There is one cafe with jazz in its name and a piano, a few hotel lounges with a trio on the weekend, and a brewery with a house band that will play a standard if asked, and that is the scene. Bangkok has the jazz, two hours up the motorway, in a dozen rooms with a proper trio and a door charge, and if the saxophone is the point of the night, that is where it is.
What Pattaya has instead is musicianship in the rooms that do not say so. The list above is built from reviews that mention the playing, the guitarist, the singer's voice, rather than the genre, and it finds the rooms where people who know music go: the brewery, the roof at Moon Whale, the Hard Rock's house band, the bands on Walking Street at Hot Tuna and the Stones House, and Bodega on Soi Buakhao, where the house band plays a set list that wanders further than most. None of them is jazz. All of them are played well.
The honest list is short because the honest answer is short. The site could have padded it with lounges that play jazz through the speakers, and did not.
A band you can see count in
We are not jazz and say so at the top of the page. What we have is a house band six nights a week, three metres from a table, in a cold room, playing rock and pop and the songs a hall of British, Australian, Scandinavian and Thai regulars can sing, and playing them with the tightness of a band that has done the same stage for years. Anyone who came for jazz and stayed for the second set has usually said something about the guitarist, who plays the solos that were saved for him and does not overplay them.
The nearest thing to a jazz night at our counter is a Sunday, when the band plays the room rather than the set and takes requests it would not risk on a Friday. We have heard things on Sunday nights that a jazz room would recognise as improvisation and we will not describe them, because you would not believe us.
The list above is Google's rating weighted by review count, the rule stated so you can argue with it, and each entry has its distance from our counter. Josh's cafe with the piano is the one to try if you must have a piano. We are at the back of the hall on Soi Diana for the rest.