Travel in the Schengen area for UK citizens after Brexit.
ETIAS
The European Travel Information and Authority System (ETIAS) will be fully operational in 2024. For updated information check https://www.schengenvisainfo.com/etias/.
The ETIAS is a waiver program that will allow citizens with valid passports from over 60 countries (including the United Kingdom) to apply for visa-free entry into the Schengen Area. It is important to remember that although UK travellers will not require a visa, they will be required to make arrangements with European authorities with sufficient time before travelling, which will mean an online application for ETIAS.
Once approved, ETIAS waiver holders from the United Kingdom will be eligible to stay within the Schengen Area, visiting as many countries as they please, for up to 90 days within 180 days. Note: An ETIAS is valid for multiple entries as long as 90 days of stay within the Schengen Area has not been exceeded over a period of 180 days.
Pilgrims walking the Via Francigena from Canterbury to Rome will enter Schengen as soon as they arrive in France. Switzerland is part of Schengen, even though not in the EU. It is entirely possible for most to walk Calais-Rome in 90 days, given reasonable fitness, and still take the occasional day off.
If, however, once these constraints apply, and you find yourself likely to outstay the 90 days, contact the nearest British embassy or consulate for advice.
https://www.gov.uk/world/france
https://www.gov.uk/world/switzerland
https://www.gov.uk/world/italy
The ETIAS waiver application when necessary can be completed online unlike typical visa applications, which need to be completed in person at a consulate or embassy.