How would a lease affect my tax residency?

I'm a US-Polish dual citizen with a remote job in tech planning to move to Europe in September. My startup is based in both Sweden and the US, and my employer is very willing to let me live and work in Europe, especially since I won't need a visa to do so. I'm interested in potentially moving to Poland at the beginning for a short while (ideally 8 - 10 months) because I miss it dearly and I'd love to improve my Polish. In fact, I already have a plane ticket to London for early September and can potentially move anywhere in the EU from there. The problem is, I desperately want to avoid paying Polish taxes, as it will cost me around $13,000 more per year than what I pay now. I understand that someone is considered a resident for tax purposes after being in Poland for 6 months. The 2023 tax year shouldn't be a problem, as I'll only be in Poland for about 4 months, but what about 2024? I'm not trying to evade the Polish tax system here or do anything illegal. I'm just concerned because I've heard that leases in Poland are usually a minimum of 12 months. I don't mind living in a different country and paying double rent for a few months at the end of the lease (let's say June-August 2024 if I sign a lease that ends by September 2024). But how does Polish law establish someone's tax residency? I'd hope the government doesn't equate having a lease and paying rent with residency if I'm not physically present in Poland for more than 6 months in 2024. Any advice or insight here would be greatly appreciated!

The first thing they will look at is 183 days residence. If you have more than this threshold and it will be difficult to avoid tax residency status.

Second test would be where your vital interests are.

A lease in itself would not affect your vital interest - tax authorities don't use this as a test because people could simply set up leases in some cheap country like Albania and use that to claim that they were tax resident elsewhere.

To test your vital interests they will look much more at where your wife, kids, pets etc are based. If these are all still outside Poland then it's gonna be very difficult for them to claim you are tax resident and win such a case in court.

Do you know if the 183 days rule applies only to a single tax year, or if 183 consecutive days across multiple tax years counts as well to establish residency?

I have to tell you that there is no such thing as vital interests for Polish tax dept.Tax dept in Poland will simply look at ya 183 days residence permit,so cover yourself for that.That includes not just staying/living in Poland but it means in the whole Schengen countries.Your children wife/hubbi maybe living in the US like mine and me sometimes(depending on $ rate) made more in Poland.Your signing of lease or owning a property has nothing to do with it.If the tax dept wants they can get your travelling data,may take a while but then they will come at you with heavy interest and penalties.I have a friend who is now fighting for mils of USD the Polish tax dept wants from him for living in Poland for years now.

It refers to a single tax year. It means 183 days in Poland.

Plus of course your centre of interests. There are quite a few factors that they take into consideration; the ones you mentioned and also a few more. It's a good idea to keep boarding passes etc. That saved me a very big bill a few years ago.

One problem with that is that the Urzad Skarbowy make quite arbitrary decisions which you have to argue about later.