The UK's newly defined relationship with the EU signals a new era of cooperation between the two powers.
There are some changes for Britons visiting the continent, but one travel agent based in Wakefield insists this can take place with minimal disruption.
Samantha Harvey, Oneworld Travel:
Will I need a visa to go on holiday to the EU?
The conclusion of the transition period marks the end of freedom of movement rights between the UK and EU.
UK citizens can go on holiday or take a business trip to EU countries but it will not be as straightforward as before.
For short trips to most EU nations, as well as Iceland, Liechtenstein, Switzerland and Norway, tourists do not need a visa and you can stay for up to 90 days in any 180-day period.
Different rules apply to Bulgaria, Croatia, Cyprus and Romania, where visits to other EU countries do not count towards the 90-day total.
A visa or permit may be needed to stay for longer in an EU country, to work, to study, or for business travel.
Travel to Ireland has not changed.
It is worth bearing in mind that the ongoing coronavirus pandemic is likely to continue to affect travel rules this year.
Do I need to renew my passport?
From January 1, to visit most countries in Europe you will need to renew your passport if it has less than six months until it expires, or if it is more than 10 years old.
The renewal process costs between £75.50 and £85. Passports are now being issued with a new post-Brexit blue design.
Will there be more border checks?
At border controls, British travellers may need to show a return or onward ticket, show they have enough money for their stay and use separate queuing lanes from EU citizens.
UK citizens will not be able to take meat, milk or products containing them into EU countries, apart from certain exceptions such as infant food.
Can I take my pet abroad?
The pet passport scheme between the UK and the EU ends today and any animals taken into the EU will need an Animal Health Certificate.
The UK Government is advising people to allow a month to arrange this and any other vaccinations their animal may need.
Will I be able to access healthcare in the EU?
UK nationals in the EU can still access healthcare, as can people from member states in Britain.
The European Health Insurance Card (EHIC) allows British citizens to access state-provided healthcare during a temporary stay in an EU country.
Existing EHICs will remain valid until they expire. Applications for new cards will see people receive a new UK Global Health Insurance Card (GHIC) to help them get emergency or necessary medical care.
From today, GHICs and most UK EHICs will not provide cover in Norway, Iceland, Liechtenstein or Switzerland and people are advised to take out travel insurance.
The Government has warned that an EHIC or GHIC is not a replacement for travel insurance, advising travellers, including those with pre-existing conditions, to get insured.
Will I be able to drive over to Europe?
Yes, but you will need extra documents.
UK motorists entering EU countries will need a green card and GB sticker if taking their own vehicle from today.
Green cards provide proof of vehicle insurance when driving abroad and should be requested from your insurer at least six weeks before travel.
An international driving permit (IDP) may be needed to drive in some EU countries and Norway if someone has a paper licence, or their licence was issued in Gibraltar, Guernsey, Jersey or the Isle of Man.
Travel agent Samantha Harvey's top tips for travel for 2021:
Make sure you know the requirements for coronavirus testing and inoculations of your destination
Go to a travel agent