Easiest Way Hydra to Nafplio

Will you be getting a car for the Nafplio portion? There are ferries from towns in the Peloponnese. We took one from Ermioni - drove in from Nafplio, returned our car, and ferried to Hydra.
It was a short ferry trip, like 30 min, and within an hour or so drive from Nafplio making it faster than going back to Athens. You could ferry from hydra and pick up your car near the port, then drive to Nafplio.

But if you wont have a car, I’m not sure about public transit from Nafplio to this or any other port. Maybe there’s a reasonably timed bus or you could arrange a taxi?

As far as I know there has not been a ferry route like that in decades .... there is in fact no ferry into Nafplio. There is not an easy way without renting a car, and then there's the challenge of drop-off fees. As the other said, you would have to take a ferry to the port, then find a bus .,.. sometimes 2 busses. And they don't go frequently, AND it's hard to locate a timetable.

You've had an extensive thread on your itinerary, and it seems you are still hooked on the notion of Hydra first. I'm not sure why -- except it is promoted tirelessly by the Rick Steves organization. AND the main reason I can figure out is that the RS tours are almost all on the Mainland... so they throw in Hydra as a 1-day or an overnight experience from Pireaus.... the RS tours have a place they put their group up, overnight. (Tammy loved it she says). And there's lots of "eye candy" on the internet about Hydra, a couple of novels, and a movie. Despite my 13 extensive trips (3-4 weeks) and stays on about 25 islands and a dozen mainland destinations, I have not made it to Hydra, for several reasons.
• I love swims on sandy beaches, and Hydra has none... check this website for the truth: http://www.greekisland.co.uk/hydra/hydra.html
• U may like idea of no-cars, but I like to have a taxi or a bus once in awhile... to get to most "beach-like" areas is a looong walk
• Because the harbor is picturesque, every day there are lots of tour boats with tourists walking around buying souvenirs, but not much else going on.
• My Athens friends tell me Hydra is for rich Greeks & celebrities, fancy houses & pools hidden away behind walls & hedges -- they say its fine for older people lolling around on such hideaways, having cocktails. Not so much for 15-year-olds & you, without the connections for entree (Tammy's group had each other to socialize with).

If you want a scenic beach experience, there are lovely beaches a 15 minute drive out of Nafplio, where there's more to do for you and a 15-year-old girl. Several of my favorites on Assine aren't open yet in March, but Tolo beach offers a number of choices.

I still say, go to the Argolid Area/Nafplio first, then return to Athens. Then if you want a ferry experience,You can have a very enjoyable overnight or a daytrip (only 1 hour each way) to Aegina .... it's so close that many Greeks live there & work in Athens. A few years ago I spent 2 nights on Aegina & enjoyed it thoroughly. Its port town isn't fancy, but there's a lot going on... if you go into the back streets, you are where the Greeks live & shop, it's fascinating. Here's a great illustration of Aegina trip -- a photo album of a June Day trip that shows what you'll see, from stepping on the ferry (take a "regular" ferry with deck seats, NOT a hydrofoil) - - https://www.flickr.com/photos/36264706@N03/sets/72157621604646139/detail/

I pretty much agree with Janet. I did a day cruise to Hydra/Spetses from Tolo just outside Nafplio and enjoyed the few hours on Hydra. There is no ferry from Nafplio to Hydra. It's town cascades down to the pretty waterfront. It's a lovely image anyway you look at it but it's more a "jet-setter" island with not a whole lot to do other than people watch. It's nice uphill away from the waterfront with classic architecture, narrow lanes and yes, donkeys. There is some hiking in the interior but the island is not known for beaches.

I think it's fine for a day trip but not for an extended stay.

Aegina would be a great island option as it has everything one wants in a Greek Island.

Nafplio is beautiful and a great base to explore nearby World Class archeological sites and much more.

Here's THE best website for Nafplio filled with everything you can experience in the town and surrounding area:

http://www.visitnafplio.com/

According to Rome2Rio there is a ferry from Hydra to Ermioni (20 min ferry, vs 1-1/2 hrs to Athens). There is a bus from Ermioni to Nafplio or maybe you could rent a car from there, that I don't know. Worth checking out anyway.

Thank you all for your posts. I was selecting Hydra due to RS suggestion. I am now looking at just Nafpilo and using that as a hub for everything else. Perhaps a day trip to an island.

In 2017 we went from Athens to Hydra (stayed 2 nights...loved it!), then took the ferry to Ermioni (Hermione). In Ermioni, we rented a car from Pop’s Rental Car (recommended by Rick but also others online) and then drove to Napflio via Epidavros. The car and service at Pop's was great and the fee to drop off the car at the Athens airport ten days later was not excessive. Not sure if Pop's is still renting or if recent experiences are good, but we were very pleased going this route in 2017.

We used www.pegasus-cruises.gr in September 2018. It was great and 20 Euros per person. They do round trip day sails from Tolo (a beach town close to Nafplio) a few days a week and we easily arranged a one way. It was fun as the dolphins were playing in the boat's wake. Here is the what they wrote in my confirmation. " Our ship, the MANTALENA, will come to the port to collect its passengers at about 14.00. Don’t be alarmed if you arrive at the port and you don’t see her! It has to stay out of the port in order to leave space for other ships coming and going at the time, but it will be on time for departure. Please note that from Hydra we first go to Spetses where you will have a 2 hour visit before returning to Tolo at 19.15 pm."

We took a short ferry ride over to Spetses from a point of land outside Napflion. We enjoyed it for a day and especially liked that it had more vegetation than the Cyclades.

Guessing you're landing in Athens then taking the train to Piraeus to catch the ferry to Hydra. I was scheduled to rent a car at the Athens airport next month and drive to Hydra for a few days before driving on the Nafplio (now going in September). Have you considered driving? It will be less complicated and you'll have more control/options. Don't be afraid to drive in Greece - just don't in central Athens.