8 days was a great length for us. If it was any shorter, I would have felt like I missed something. However, if you are not very interested in wildlife and nature, 5 days would probably be better for you just to get a taste of the islands. 4 days seems too short since you spend a day arriving and another day departing. I would not have minded 5 days on the boat and 2-3 nights at a hotel on Santa Cruz Island.
You do not have to be athletic at all to do the daily excursions. However, you do have to feel comfortable getting in and out of the boat that is in shallow water on a beach (with help), and you have to be comfortable walking from rock to rock. These are things you get used to with practice Hikes were 100 yards to 1 ½ miles long, but most of them on the shorter side.
If you are a very active person, a multi-sport island hopping tour might be better for you. Our “hikes” were very short and very slow. We were able to snorkel every day, and kayak twice, so that definitely helps, but for me there is not enough activity to offset all the sitting around on the boat.
We did not schedule any scuba diving on our trip mostly because I thought we would miss something on the islands if we did. It would have been alright with me to replace a couple of the snorkels with diving. However, diving is only offered in certain places, it’s very expensive (budget $250/person for a 2-tank dive), and you typically have to have a minimum of 4 divers.
The diving is also for advanced divers. One couple on another boat did a dive at Kicker Rock where the current would get so strong, they would have to hold onto the rocks tightly until it passed. Even though it was March, the warmest month, they were in 5mm wetsuits, and they were still a bit cold.
I thought there was more than enough food served (no one lost weight on this trip!). However, we would save a little extra food from breakfast and lunch for our son, who would get hungry in between meals. The kitchen people were good at giving us a sandwich at odd hours as well.
Our very first excursion, to Ochoa Beach, was not the best but maybe because the water was so rough. The excursion to Phillip’s Steps was also not great, but maybe because it was so hot and we walked so slow. I really liked all the other excursions, and I wished we had more time in Puerto Ayora.
Snorkeling equipment, wetsuits, and all soft drinks were included on our cruise, but that is not the case on all cruises, so be aware of that expense.
Bring books and games as there is a lot of down time on the boat.