There is always some current at the good snorkel spots on Kauai. At low tide, less water comes over the reef, giving the water a chance to settle and clear up. Certain areas are restricted, like Makua or Tunnels on weekends, where we have agreed not to operate tours on Saturdays and Sundays in deference to community input. Community events such as canoe races or surf meets can preempt tour operations. On each tour, the tour leader will brief you on the site, what you can expect to see, how to avoid damaging the environment, and how to snorkel and look good doing it.
Snorkeling is very easy and most people learn to relax and enjoy the experience quickly.
Just stick with the tour leader who will be looking for unusual things to point out to you. The tour leader is also shooting video, so if you want to see yourself in the video on the way back, stick close by. For those who need a little extra help, no worries. We have taught thousands of people to snorkel including non swimmers, people who are afraid of the water, even paraplegics. The tour assistants have large, soft surf boards with handles around the edges.