British passports must have been issued less than 10 years before the date of arrival and remain valid for at least three months beyond the planned departure from the Schengen area. UK travellers can still visit Portugal visa-free for up to 90 days in any 180 days, though they may be asked to show proof of onward travel and sufficient funds.
The EU's new Entry/Exit System is also being introduced across the Schengen area, meaning British visitors may be asked to register biometric details, including fingerprints and a photograph, at the border, potentially leading to longer waiting times during busy periods.