First timers planning 10 day trip - need a little help

Time will be tight on the itinerary. Be prepared to allot time to be at the ferry ports 30-45 minutes prior to sailing.
Since Crete and Mykonos have great beaches, not sure why you’d want to overnight just one night in Naxos. One-nighters are logistical time sinks and really won’t allow you to see much more than Naxos Town.
Once you finalize your itinerary, reserve your accommodations now for Santorini and Mykonos. Good-value accommodations for those two islands are already getting reserved a year in advance and prices will hit astronomical levels for August and September if you wait.

Kenko,
That is helpful to know. We decided to ferry because I thought it would be easier. I can certainly take Naxos out of the equation. My group really wanted to see Santorini and Mykonos. But so many people are telling me that it's so touristy. But it's just like our first time trip to Italy last year. Everyone said skip the touristy cities but our we ended up at Venus, Florence and Rome and it was perfect. Just takes a lot of planning. What are your thoughts if we just did 3 nights each at Crete, Santorini and Mykonos?

Santorini and Mykonos will have more tourists than locals in August/September. Both are popular for good reasons. If you can visit when there are fewer cruise ships in port, it will be better. www.CruiseMapper.com will show you which cruise ships will be in port on specific dates.
The hike to Zeus’ Cave on Naxos takes about 4 hours from the trailheads, so in August/September you need to do that early in the morning. Not sure if that’s possible with the tight itinerary.
Because Mykonos Town and Naxos Town both look somewhat similar. and since Mykonos has superb beaches, I would give Naxos a miss on this trip.
Yes- If you go to Crete, Santorini and Mykonos for the duration I think it will be a better trip.

Cruisemapper suggestion was helpful. Thank you. Decided to drop Naxos. So we're looking at 3 nights each in Crete, Santorini and Mykonos. Make sense to stay in Chaina or Rethymo? Would love more ideas for what to do in Crete. And we really don't want to rent a car? Will that be an issue?

Chania would be my choice. You can visit Rethymno from Chania ( it’s only a hour away) but with the airport and high-speed boat for Santorini departing from Chania— Chania is the place to base yourself. Chania is an Interesting town and you can also venture out of town to great beaches such as Balos and Elefonisi.

Unless something has changed, there is no ferry from Chania or Rethymno to Santorini. For that you have to depart from Heraklion, which is actually close to Knossos. Heraklion is also the location of the island's archaeological museum.

SeaJets now has high-speed boats crossing from Chania to Santorini in less than two hours.

Just 9 miles from Chania is the archaeological site of Ancient Aptera. One of the most important city-states in Ancient Greece, Aptera has origins going back to the Minoan civilization.

On Saturday morning there is a ferry from Rethymno to Santorini that leaves at 8am, as does the one from Heraklion. I understand that staying in Chania makes sense because it is closer to Balos and Elefonis. (If I had to pick a beach, which one?) But I just hate having to drive 1-2 hours to get to port so early in the morning. And my hesitancy with renting a car is navigating unfamiliar roads.

Looks like SeaJet departs from Chania in August 2025 at 8am on other days but not Saturday. On Saturday, there’s an 8 am departure from Rethymno.

Be careful not to rely on ferry schedules so far in advance, particularly with Seajets who publish schedules very early but is notoriously known for cancelling trips weeks or even days before.