Pronunciation of letters " w " and " z " in Polish

Do you pronounce the w's and z's in Polish? I've been trying to learn and they don't seem to pronounce them really as far as i can hear. Maybe I'm not listening properly?

I mean when they are on their own in a sentence.

It's like w domu is "wdomu" z Kasią is "zKasią"

Oh okay, so you attach it to the word and pronounce it like it's part of the word? Thanks!

Yes what you said, also often "z" sounds like "w" and w sounds like "f", same way it happens in Polish in general.

Try ivona.pl with phrases like
w Warszawie, we wtorek, w piatek
z Kasią, z grzybami

Cool, thanks this site is very helpful for pronunciation.