Aloha Clara,
Thank you for your interest in Dolphins and You! I'll respond to your question about motion sickness and then your question about young snorkelers.
As the other travelers have mentioned, we do offer motion sickness PSI bands for purchase at $20 for a reusable pack of two. PSI bands work by tapping into a pressure point in your wrist, which can help ease the impact of motion sickness. But for those who are prone to motion sickness, we recommend taking over-the-counter medication at least an hour before the tour begins so that the medicine has time to kick in.
In terms of the ocean conditions, they are not predictable day-by-day. But in general, the waters are sometimes a bit rougher in the winter months (December - March) and later in the day. Summer tends to be quite calm. We also have lots of activities going on whenever we are on the boat, and we spend much of the day in the water.
In response to your question about your children, 5 and 7 years old are perfect ages for our tour! Our crew is great with kids and first-time snorkelers. They'll have an awesome time with the waterslide and onboard entertainment.
All guests are outfitted with a life vest, so they will stay at the surface without much effort. And our crew is lifeguard and free dive certified. The lead guide will have a lifeguard float in the water for anyone who needs assistance. It's best to let the guides know beforehand if anyone in your group may have trouble swimming.
Please let us know if you have any other questions. Mahalo!