From the journal

Thirassia, the island Santorini left behind

7 min read

Thirassia is the piece of the caldera rim that separated from Santorini when the volcano collapsed. It is 9.3 km² with 249 residents, and for a boat it is a stop rather than a destination: Korfos at the water, Manolas on the rim above, and roughly 200 to 270 stone steps between them.

From Fira, Thirassia is the long dark line on the far side of the water that most people never identify. It is not another island in the way Naxos is another island. It is the same island, on the other side of the hole.

This is a piece about Thirassia as a stop on a boat route — what a two-hour call gives you, and what it does not. It is not a guide to living there for a week.

The same eruption, the other side

Thirassia and Santorini were one ring of land until the Minoan eruption around 1600 BC emptied the chamber underneath and the roof fell in.

What survived is three fragments of that ring: Thera at 75.8 km², Thirassia at 9.3 km², and Aspronisi at 0.1 km² down in the south-western gap. Thirassia is the north-western section, and it is the second largest island of the group.

Because it is the same rim, it has the same cliff. The layers you read on the Fira side — dark older lava at the base, thick pale eruption deposits capping the top — carry straight across the water and reappear on the Thirassia face. Standing at Korfos and looking back at Santorini, you are looking at the inside of the same wall from the opposite direction.

That reverse angle is the reason a boat stop here is worth a route detour. Everyone photographs the caldera from the rim of Santorini. Almost nobody sees the rim of Santorini from the caldera's other edge.

What arriving by sea looks like

The main port is Korfos: a narrow waterfront strip at the foot of the rim, a handful of tavernas, small stone swimming platforms, and a rocky seabed under clear water. There is no beach in the Santorini sense and no sand to speak of.

It is quiet in a way that surprises people who have spent three days in Oia. The 2021 census counted 249 residents on the whole island, down from 319 in 2011, with 140 of them in Manolas and just two at Korfos itself. Roughly seven tavernas serve the island, most of them at the water.

Boats either come alongside at Korfos or lie off, depending on the day and on what else is in. Paths are uneven and gravelly. Bring shoes you can walk in, not the ones you wore on deck.

The numbers

How to reach Thirassia, and what each way gives you

Five ways in. Only two of them are realistic if Santorini is your base and you have one afternoon.

Way in	How it works	What it gives you	The catch
Shared caldera cruise	Thirassia is a scheduled call on the fixed route. The boat docks or lies off at Korfos.	One to two hours ashore, which is a taverna lunch or a swim, and occasionally the climb.	Not enough time for all three. The route belongs to the captain, so the length of the call is not yours to set.
Full-day private charter	Ten hours, 10:30 to 20:30, on your own boat and your own clock.	Time to walk up to Manolas, look back at Santorini, come down and still swim before lunch.	€2,400 for up to 10 guests, then €100 each — €240 a head at ten, €182 at seventeen. A private boat is never cheaper per head than a €100 shared seat.
Caique from Ammoudi	Small boats run from Ammoudi below Oia, about 20 minutes across, three to four daily in season.	The cheapest independent crossing, and the shortest. You go on your own schedule.	You are tied to the return sailing, and Ammoudi itself is a long descent below Oia.
Car ferry from Athinios	Vehicle ferries cross from Santorini's commercial ferry port.	You can take a car or a scooter across, which is the only way to see the far end of the island.	Athinios is about 8 to 10 km south of Fira down a hairpin road, and it is a bottleneck at ferry peaks.
Scheduled ferry from Piraeus	Thirassia is a scheduled call on at least one Piraeus to Anafi routing, not only an excursion destination.	You can arrive from Athens without setting foot on Santorini first.	Infrequent. Check the timetable for your actual date rather than assuming a daily service.

Access details from the Municipal Port Fund of Thira's Thirassia page, ferryhopper.com and en.wikipedia.org, all seen 25 August 2026. On our cruises the boat anchors offshore at swimming stops — none of them has a jetty — and your exact meeting point is confirmed with your booking.

The steps

From Korfos a stone stepped path zigzags up the rim to Manolas. Nobody agrees how many steps it has either: 270 is the figure most sources give, one publishes 214, another says about 200. So we write roughly 200 to 270 stone steps and leave the argument alone.

It is a steep zigzag on uneven stone, in full sun for most of the day, with no shade and no water on the way. Mules are still worked on the island's paths and can be hired for the climb.

The honest verdict for a boat stop: inside a one- to two-hour call, the climb is the whole call. You will go up, look, take the photograph and come straight back down, and you will not have lunch. If the climb is the reason you came, book the full-day private cruise, which has room for it, rather than squeezing it into a route that does not.

What you are looking at from the top

Manolas sits on the rim directly opposite Santorini, 140 people at the last census, with two churches and a line of houses along the edge. From there the whole caldera is laid out the other way round.

Fira is a white seam along the cliff to your right, Imerovigli above it at the high point of the rim, Oia at the far northern end. In the middle sit Nea Kameni and Palea Kameni, the two islands that grew back inside the hole after the collapse. From Santorini they look like the centrepiece. From Manolas they look like what they are: new ground, low and dark, sitting inside a much older ring.

It is the one view on the whole caldera that explains the geometry without anyone having to draw it for you.

What a boat stop is not

A stop is a stop. If you want Thirassia itself — the walk to Potamos, the far side of the island, an evening there — take the caique from Ammoudi or the car ferry from Athinios and give it a full day of its own. We can put you ashore for an hour or two on a cruise, and that is a genuinely good hour or two — the Thirassia stop page covers what it looks like on our route. It is not the same thing, and we would rather draw the line ourselves than let you find it at 15:40 with the boat waiting.

Ready when you are

The day with room in it

The full-day private cruise runs 10:30 to 20:30 — ten hours, up to 17 guests, and enough of a margin that Thirassia can be a proper stop rather than a wave from the water. Send us a date and the number of guests.

Check availability & book

Call the harbour office+30 698 977 1888

Common questions

Thirassia — is it worth a stop?

Yes, for the reverse view and the quiet, if you accept what a stop is. One to two hours at Korfos gives you a swim off the stone platforms or a taverna lunch. It does not give you the island. If you want that, cross independently and spend a day.

How many steps are there from Korfos up to Manolas?

Published counts disagree: 270 in most sources, 214 in one, and about 200 in another. We write roughly 200 to 270 stone steps rather than picking a side. It is a steep zigzag on uneven stone with no shade, and mules are still worked on the island's paths if you would rather ride.

How long do boat tours stop at Thirassia?

One to two hours is typical across the market, and that is the working figure on a shared caldera route. It is enough for one thing: lunch, or a swim, or the climb. Trying to fit all three into a two-hour call is how people end up running for the boat.

Can you get to Thirassia without a boat tour?

Yes. Caiques cross from Ammoudi below Oia in about 20 minutes, three to four daily in season. Car ferries run from Athinios if you want a vehicle across. Thirassia is also a scheduled call on at least one Piraeus routing, so you can arrive from Athens directly.

How many people live on Thirassia?

249 at the 2021 census, down from 319 in 2011. Manolas has 140 of them, Potamos 74, Agia Irini 28, Agrilia five and Korfos two. The Municipal Port Fund's own page still quotes the older 2011 figure, which is worth knowing if you see 319 published somewhere.

Is there a beach at Thirassia?

Not in the Santorini sense. Korfos has small stone swimming platforms and a rocky seabed under clear water, which makes for a good swim and a poor sunbathe. The island is roughly 9.3 km² of rim with steep sides, so there is very little shelving shore anywhere on it.

Santorini Boat Tour - Water Taxi is a catamaran cruise and water taxi operator based in Fira, Santorini.

Updated August 2026