The UPC campus is covered by the eduroam Wi-Fi roaming for research organizations. If your local institution provides access to eduroam, you will automatically have Internet access at UPC.
Otherwise, connect to the XSF-UPC access point. In the capture page (appears automatically on some operating systems or while trying to open a webpage), enter
You can also press the “connect as guest” button. You will have access to the HTTP(s) ports, but not to SSH, POP/SMTP and other ports.