Lonna is a small island between Helsinki and Suomenlinna, reached by a ferry that takes about fifteen minutes from Market Square. The sauna sits by the shore, in a restored building that matches the rest of the island’s stock.
Two saunas of identical layout face the sea, with a terrace between them and steps down to the water. Reviewers describe the setting as the reason to come, and it is the single most consistent point of agreement in the corpus.
The reviews split cleanly after that. Visitors who booked ahead and came off-peak describe an idyllic afternoon. Visitors who arrived at a full session describe changing rooms too small to turn around in.
What is the sauna experience like on Lonna?
The two saunas are wood-fired and run identically, with the pouring done collectively — reviewers describe a room where visitors take turns adding water rather than one person controlling it.
Arrival includes a short briefing and a basket with a locker key, a cup for drinking water and a small seat towel. The seat towel is the source of one recurring complaint: several reviewers describe other guests not using it and sitting on the wood in swimwear.
Swimming is off the rocks, down large slabs from the terrace. Reviewers repeatedly warn that the descent is uneven and slippery, and recommend water shoes. One visitor with limited mobility used the showers instead and said so plainly. Cruise ships pass close enough to watch from the water.
Is Lonna suitable for a relaxed visit?
This is where opinion divides. A booking system is in place, and several reviewers credit it for a comfortable session with room on the benches. Others describe sessions sold beyond what the space handles, with constant traffic through the door making it hard to hold the heat.
The changing rooms are the specific bottleneck, and the complaint recurs across several years and languages. Multiple reviewers make the same suggestion independently: admit roughly a third fewer people at once.
Sessions are described by some visitors as too short, with more than one wishing for an extra half hour.
What should visitors know before going?
Ferry tickets are bought separately from the shipping company, not with the sauna booking, and reviewers who missed that turned up having paid for a crossing they could not use. Booking is required; the trip is wasted without it.
Towels are rented on site for an additional fee. Lockers come with the basket, but at least one visitor reported footwear stolen from outside the building, so leaving anything on the terrace is a risk.
There is a restaurant on the island, which requires its own reservation and which reviewers rate highly. Drinks are sold at the sauna and are expensive.
Directory details
Plan your visit
Lonna Sauna · Lonna island, 00190 Helsinki. Two wood-fired saunas · Booking required · Ferry ticket bought separately. Use the live listing card and map on this page for the current rating, review count and route link.
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Frequently asked questions
How do visitors reach Lonna Sauna?
By ferry, roughly fifteen minutes from Market Square. Ferry tickets are bought from the shipping company separately from the sauna booking.
Is booking required?
Yes. Reviewers who travelled without a reservation were turned away after paying for the crossing.
Can visitors swim in the sea?
Yes, off large rock slabs below the terrace. The descent is uneven and slippery, and reviewers recommend water shoes.
Are towels provided?
A small seat towel comes with the basket at arrival. Full towels are rented separately for a fee.
Is there food on the island?
Yes, a restaurant that reviewers rate highly. It requires its own reservation.
Location
Find Lonna Sauna on the map
Check the location and open directions before you set out.