To ask where you'd recommend for a thermal spa (ie natural hot springs) that isn't any of the following

[Fragmentedbrain]

1. In Iceland
2. In Hungary
3. With rules compelling nakedness (ideally with noone being naked but I'm a realist so just somewhere I can keep my swimming costume on and eyes lowered is great)

Harz Mountains...Bad Harzburg. Or the hotel near Frankfurt airport with a revolving cocktail bar but I don't think it has mineral springs.

I went there recently, they said one of the pools was a mineral one. But the whole place was lovely.

Therme Vals in Switzerland, designed by Peter Zumthor. On my bucket list! x

https://7132.com/en/therme/7132-thermal-baths-peter-zumthor/

Another vote for Ischia - was lovely

(Also my skin felt amazing afterwards)

Denizli, Turkey

Come to British Columbia! We have quite a few, from undeveloped pools amongst the rocks, to developed hotel/spas. My DH and I did a 'hot springs road trip' one summer in the Kootenays area, and we also went boating with friends along the north coast to several wilderness hot springs. Both were memorable trips.

One that stands out is Halcyon Hot Springs along Arrow Lake. Here's a link:
https://halcyon-hotsprings.com/hot-springs/

Baden Baden?

Jasper, Canada

There is one in the south or middle of Spain somewhere, but I can’t for the life of me think where. It’s a daft old fashioned hotel in the middle of nowhere. Wierdly my friend appeared on a work trip. Very odd coincidence!
sorry not much help, but I’ll have a google.
these all look amazing.
mdinbc a boat trip to hot springs in natural pools, wow!

Most German spas or German-speaking areas of Italy will mandate nakedness in saunas.

i highly recommend QC terme places in Italy. In particular San Pellegrino, Bagni Nuovi, Bagni Vecchi or the one near Milan. They are excellent value and very high quality.

La Fortuna in Costa Rica is the only one I’ve been to - long way to go but plenty of other amazing things to do while you’re there!

We stayed at Tabacon which was £££ but the hot springs were amazing.

Rotorua is amazing if you fancy a trip to NZ

No it's not. It's boring and backward as feck and the food and accommodation is absolutely dire. The car drivers are maniacs. My worst ever holiday.

Came on to say the same!

There is a small but nice spa in Bad Endorf in Bavaria, near Chiemsee. The sauna part is "textilfrei" but you wear your swimsuit in the indoor and outdoor pools.

There's a whole side that is swimwear compulsory. With warm mineral pools. Warmest up to 38° iirc.
Only the adult only saunas and steam room side requires you don't wear swimwear

Krakow, there’s a theme one, but also a few undeveloped ones that are free to use.

The Grotta Giusti in Tuscsny - breathtaking! https://www.grottagiustispa.com/en/

Saturnia

Azores has them and beautiful island. We went to Octant Furnas, very scenic, lovely food. Went in March and great value then. Hired car and was fine. Is like going back in time but part of it's charm.

There are many in Catalonia look for themes, somt hotels have a private pool under the hotel room , Caldes de mont Boí is wonderful

Also spa in Belgium. Spa high up overlooking the treetops. Very special

Ischia. Poseidon Gardens are glorious but there are others.

I was going to say the Azores. I had the exact opposite holiday to you 😂
The landscape was beautiful and the people were lovely and we stayed in the most beautiful hotel. One of my favourite ever holidays!
Also the springs in Saturnia, Italy are lovely too.

I love a mineral spa and find Central Europe/Balkan countries gla good, low-key option. Confidently flights are cheap so can go a few times a year.

Bulgaria has loads and it is a beautiful country full of mountain ranges. Spa towns I have visited include Velingrad, Pavel Banya, St Constantine and Helena and Banya/Dobrinishte just outside Bansko. They are joining the Euro next year and it is a country I have fallen in love with. Slovakia also has lots of thermal areas, as does Romania (Transylvania is stunning) Serbia, Slovenia, Turkey and Slovakia. All very affordable, great food and beautiful scenery.

I am currently planning a solo trip country hopping after flying in Bulgaria next month. Many of my stop offs seem to be conveniently near to thermal/mineral pools! I often stay in small local guesthouses/apartments and pay entry into pools but often the attahced hotels have a half board package to make things easier.

I know you said not Hungary, but I love Hajduszoboszlo. The quality of the mineral water is incredible. All of the places mentioned are used by locals (often prescribed services as well as for leisure) and nudity is not the norm. Germany and Switerzland are very strict that no textiles are warn in the sauna zones so avoid if this would be an issues.