Hi Leo!
My husband and I just did our open water certification dives with Seasport and we were really please with them. We did our first two dives from the shore at Koloa landing a little late in the day, and it was quite surgy/choppy. But it was doable for us newbies, so you should do just fine. There seemed to be quite a few shore divers there though. One in particular is there almost every day, per our instructor. We heard whale song on our first shore dive and saw quite a few turtles and eels both times. Visibility was not as good as on the boat dives - the shore dives maybe had a vis ofa about 40 - 50 ft.
We did our last two dives from the Seasport boat at Sheraton Caverns (again lots of turtles!) and Stone House (might have this name wrong). Nice boat (although this was our first dive boat experience - so nothing else to compare it to) and really good crew. Sheraton Caverns is a pretty far swim for a shore dive but a nice site.
I am so jealous! You are going to have a great time! Say hi to the folks on the sunset wall at Poipu for me!
BTW - the Poipu Grill is a few doors down from Seasport Divers in the same shopping complex. Just a hole in the wall - literally, but great and inexpensive for lunch or dinner. Try the grilled fish sandwich. Also, if you like fish, the Kaloa Fish Market has really good local plates and poke.