I bought walk-in tickets for two which costed an extra 100 or so than if I had booked via Klook, so remember to do your research. The 8 islands tour was amazing, simply all you expected for a tour like this. Our leader, Pattrick (Pat) was communicative, funny and super helpful. He took a lot of photos for us. The first 30 minutes was probably the worst as waves were so strong, but after that all was OK. We got to swim at the largest fresh water lake at the Pregnant Maiden island, watched the eagles and tried the echoing, go super close to the limestone cliffs, had 10 minutes free ride, and swim and snorkel at a beautiful small island. It was brilliant.
Side note: my sister and I tried the jet ski for the first time.