I have never changed money in a bank and for years now have used the Hotel Eolo at the traffic rounabout right in the centre of the seafront.
It is so convenient , no commission, no passport and the staff excellent in English and very pleasant to deal with. Also their rates are as good as any and better than a lot.
Beware of a place which shows quite a better rate. It might not have a notice saying No Commission and you could get stung.
There are several 'holes in the wall' & that's all I ever use. There are some along the Formentor Road outside the banks, in the main Juan XXIII road & also now one in the Caprabo supermarket. You can select the language for the instructions. There are also cash points at the airport. I normally make sure I have some euros before I go (The Post Office usually has good rates) & then use cash points for the rest.
I do now have a Spanish bank account anyway but it's what I would do in any european country (& the US).
By the way, prepared to have to show your passport for ID if you use a Credit Card at shops & the supermarket.
Penny, We concur with Pollensa, that's exactly what we've been doing for years now! But, you will be charged commission from your bank and this will attract a minimum fee,, so it makes sense to draw as much as your allowed which keeps commission to a minimum. Another advantage from this method is you should get the bank rate which should beat any rates available in the port.
Don't tell me! Our last holiday on mainland Europe we were burgled on our second night by illegals, my handbag with phone, Bob's wallet with cards, cameras you name it all went - while we were asleep!! Scary or what. We stick to islands now!