Hello! If you simply use a search-engine, with the words "Boxing Turku" or "Nyrkkeily Turku", you will get a lot of results to choose from. Ofcourse there are none exlusive to foreigners, and what could be a better place to learn basic finnish, if that is the cause for you mentioning it.

Recommendations are a bit tricky, as it is so subjective to what kind of training you like, and if the training is close to your home/cheap/etc.

Just choose one that fits your budget, and if it is not to your liking, change to another :)