My girlfriend and I did this dive 4 times in a row during our trip to Kona last week, once as a snorkel and three times as a dive. The entry and exit isn't too bad (if you are used to climbing up and down rocks) if the surf is small. We parked at the Sheraton and followed the sign for shoreline access to a path and walked down to where the trail entered and basically entered there. It was nice that the Sheraton has those tiki torches, they make the exit easy to spot and navigate on a clear day. You will want to make sure you time your visit correctly. I believe most of the tour groups start getting people in the water around 6:30, at least in December. It's great to go dive under one of the snorkel groups as there lights attract the mantas. The first night we did the dive as a snorkel just to make sure the entry and exit was easy. This was easily one of our best nights so I feel snorkeling it gives you pretty much the same quality of experience. Some of the boat operators may be rude to you and say stuff such as 'get away from our people'. Just ignore them and pretend you don't hear them. It's a free ocean after all. That first night the Manta's stayed with us and our lights after the tours left, but every other night they left when the tours and their giant lights left. Perhaps having the lights at the surface (snorkeling) is better at attracting them, or perhaps it was just chance. On other nights the Manta's left when the tours left. Also, one night we went when there were no tour boats out (we got out there late) and we only saw one Manta and it did not stick around with us. So time your visit right. Anyhow we loved this experience and loved the fact that we got to do something 4 times for free (or for the price of a tank rental) that everyone else was paying over $100 for. If the surf is small I highly recommend it. Just enter at the end of the trail and swim out towards the platform and then to the dive boats when you see them. Be careful not to get too close to the boats, especially the glass bottom boat which keeps it's engines live. That boat is only there on Tuesdays and Thursdays though. It comes later in the evening, around 7:30-8pm.