We opted to do a sunrise kayak tour of the islets and we had the perfect guide.
We arranged this with our hostel and a taxi picked us up at 5am so we were in the kayak and on the water in time for sunrise.
Vladimir has lived in Granada for 25 years and knows the islands so well. He showed us all the islands had to offer, spotting birds, plants and monkeys along the way. We fed monkeys, kayaked through water lilies and had water melon under a tree in still water. It was the most perfect start to the day. I would recommend seeing the islands this way as you miss the boat traffic of the tours and it is such a tranquil experience.
Cost $25 pp including taxi from the hostel to the transport.