High. As long as this text is up, there is about a 90% chance of seeing at least one manta. That will change in the next few years as the manta industry gets regulated. For right now though, the probability is so high due to the ability to choose what manta site we wish to visit. If our north site didn’t have mantas before, we will go to the south one for our next trip. It is very rare for neither site to have mantas.