UK citizens (including children and infants) must have their own full 10 year (5 year for children) passport with at least 6 months’ validity remaining on your date of travel.
Brexit: If the UK leaves the EU with no deal, the rules for travel to most countries in Europe will change from 12 April 2019. If your adult passport was issued over 9 years ago, you may be affected. You should use this tool to check your passport is still valid for your trip before booking travel. If you renewed your passport early, extra months would have been added to your new passport. Any extra months on an adult passport will not count towards the validity requirement, so some passport holders will need to have more than 6 months remaining in order to travel.
You must ensure that you're familiar with the UK Government's guidance on passport rules for travel: https://www.gov.uk/guidance/passport-rules-for-travel-to-europe-after-brexit
Guests holding a "British Isles" passport issued in the Balliwicks of Jersey or Guernsey or the Isle of Man may not be entitled to the same entry exceptions when visiting countries abroad as a guest holding a full UK passport and this should be checked carefully with the embassies of the countries you will visit on your itinerary.
Guests holding non UK or ROI passports should check with relevant embassies.
For further passport, visa and health advice for your destinations please visit the FCO (UK) or DFA (Ireland) websites, have a look at our visa page or refer to our Booking Conditions.
ESTAs are mandatory for everyone travelling to the US. You must apply for an ESTA no later than 72 hours before departing for the United States. Real-time approvals are no longer available and arriving at the airport without a previously approved ESTA will likely result in being denied boarding. Some other countries also run similar programmes – so make sure you've checked the requirements well in advance.