Seeing as you have no reply:-
There is not much in the way of sea fishing, there are some locals that offer trips on long tail type boats, but this is just a side line for some operators who have nothing better to do on that day. Coastal fishing is a bit hit and miss, there is a dead coral reef running much of the length of Khao Lak, killed during the mining days, and dead coral does not attract much in the way of fish, and limits the coasting fishing as you will lose your terminal gear. Some locals know the “holes” but they are largely after bait fish, and there aren’t many of them these days. Also, the big issue you will face is August is the raining season, and seas are quite choppy, limiting further any fishing activity.
On the positive side there is some excellent fresh water fishing locally, with substantial size catches, bit of a commercial fishery, but in excellent location and good if you need to “wet a line”. Just search TA if you are interested.
There are no boats in the water from May to October.
The sea fishing is actually good here. Dorado, Albacore, Emperor Mackerel, Snapper, Grouper and a wide variety of local fish. longtails are cheap and easy to charter for the day. Appx. 3500 Baht and includes rods, bait, fresh fruit, lunch and soft drinks.Edited: 22 October 2018, 16:54
Modell can you post the company you are talking about (or PM me if it is yours). My family went on a sea fishing trip on our last visit which wasn't so good so we are looking for another option.