It is pretty quick. The water was cold but it was enjoyable as it was 90+ that day. Line was short so we did it twice. If you take your time it can last 5-8 minutes or you can skim across the top and be done quickly. They do not allow you to stop and hold on to anything so grab a vest if you are not a good floater or swimmer. Lots of fish and water was very clear.
It was my DS8 at the time favorite thing we did the entire trip, he had to go twice actually. Now if you don't like or have a fear of sharks this may not be for you.
DD6 & I didn't get along with this too well. DD couldn't figure out the snorkel & I was breathing rapidly due to the cold water LOL. DW was a little better. DD11 was a pro. She did it 5+ times both days we were in TL