UK – EU
EU states and several non-EU states are part of the Schengen area. Ireland and the UK are outside the Schengen area and have continued and will continue the Common Travel Area.
After Brexit, a British citizen will be a third country national under the Schengen border code. They may remain up to 90 days in the Schengen area. He or she must have a passport issued within the last 10 years with sufficient unexpired validity to cover at least the date of intended departure from the last country visited in the Schengen area.
UK-Ireland
The Common Travel Area is an arrangement between the United Kingdom, Ireland and the Crown dependencies of Jersey Guernsey and the Isle of Man. It ensures that British and Irish citizens can move freely between and reside in the other country or territories.
Irish citizens will continue to have the right to enter and remain in the UK after Brexit. The same will apply to British citizens resident in Ireland. The rights include the right to work, study, vote, access to social welfare benefits and health service. This is subject to compliance with the terms of the relevant legislation in the host state.
It is contemplated that there would be no routine immigration controls on journeys within the Common Travel Area. It is also contemplated that immigration laws will remain aligned at least between the UK and Crown dependencies.
Persons who are neither Irish nor British citizens must continue to meet the relevant entry requirements for the jurisdiction which they propose to enter. Accordingly, they may be subject to UK or Irish immigration controls in accordance with their nationality or status.