Though not home to Thailand's best dive sites, Pattaya's proximity to Bangkok makes it a popular spot to get some underwater action. However overfishing and heavy boat traffic mean the sites closest to Pattaya can be barren with poor visibility. Nearby Ko Larn, Ko Sak and Ko Krok are good for beginners, while accomplished divers may prefer the outer islands of Ko Man Wichai and Ko Rin, which have better visibility and marine life.

In most places expect 3m to 9m of visibility under good conditions, or in more remote sites 5m to 12m. Further southeast, the shipwrecks Petchburi Bremen, off Sattahip and Hardeep, off Samae, have created artificial reefs. The scuttled Thai navy vessel HMS Khram sits in 30m of water off Ko Phai, and many operators offer excursions around the sunken hulk. One of the best dive sites is an old US navy ammunition dump called Samaesan Hole. This advanced dive goes down to 87m and has a gentle slope covered with coral where you can see barracuda and large rays. Visibility here is up to 20m on a good day.