Will my new Apple Tv 4K box work when i travel to the UK?

Yes, as stated. I always pack my Apple TV when I travel. However, If you stay in major hotel chains, they often lock down their networks so you cannot add networking devices like an Apple TV. They do this so they do not have to provide additional bandwidth.

I have confirmed mine works fine in Portugal, Ireland, Azore Islands and all over the USA including Hawaii & Alaska. Later this year, I will confirm it works okay in Italy, however I'm not too concerned.

The Apple TV box will work in any country, although services will be different by country.

The only hardware regional part is the power plug. You may need an adapter, or buy a local replacement C7 power cable (probably a few % cheaper if you don’t have a spare adapter already).

Some services to which you subscribed may only work in the former home country (national services like TV networks). Often checks are done for IP address geolocation.

Other services may work worldwide, although their catalog may differ a bit by country (Netflix, Prime).

Subscribing to UK services may require a UK payment method linked to your Apple ID, which means changing the country setting for your Apple ID. Which in turn requires ending subscriptions for the former county. Switching the country for an Apple ID would also possibly make some purchases from the former country inaccessible for the duration. Some groups of users may be better off creating a secondary Apple ID account for the new country – depending on use and duration.

Yes.

Content in some Apps may different, and some apps may not work at all, but the Apple TV box will work.

When you get to the UK just set up a new user account registered in the UK. It's easy to switch back and forth between your current user account and the new one. When your are using your new UK user account, whenever you go to the Apple Store you will be connected to the UK Apple Store and can download apps like BBC iPlayer which aren't available in US Apple Store.

When you come back to the US just switch back to your US account.

As others have said some Apps will not work across geographies .

GromitD90 wrote:

When you get to the UK just set up a new user account registered in the UK.

No, that is terrible advice. It requires they have a UK payment method. And will cause separation of content. There is no reason to suggest this at all. If they are moving to the U.K, they can change the region for their Apple ID then. If they are not, there is absolutely no reason to create a new account just for the trip.

It's easy to switch back and forth between your current user account and the new one.

On an Apple TV, yes, it easy. On any other Apple device it can lead to one account being locked out from the device for 90 days.

When your are using your new UK user account, whenever you go to the Apple Store you will be connected to the UK Apple Store and can download apps like BBC iPlayer which aren't available in US Apple Store.

Correct, but again, unless you have a UK payment method, you won't be able to use any of the subscriptions on these apps, so the option is pretty pointless. And I doubt anyone who is just there for a short trip wants to subscribe to app's , pay for full month and and the have to cancel them and waste the rest of subscription cost.

This is just more trouble than its worth.

I was able to set up a UK account without providing a payment method. I can only download free Apps but most of the TV apps are free anyway.

I only use my UK account for Apple TV and have no issues .

Changing the Region setting does not let you connect to the Apple Store of the selected region.