Have to get from terminal 5 to terminal 1 at Heathrow for a connecting flight. How do I do that? How long will it take? I am a US citizen so would I have to clear immigration before changing terminals? And how long would that take? Traveling from US to Heathrow to Dublin. Please advise. Thanks!

Why not go straight to the horse's mouth?
http://www.heathrowairport.com/heath...ween-terminals

This is a better link, specific to your question:

http://www.heathrowairport.com/heath...-international

I do not believe you have to to go through immigration at Heathrow - just follow the "flight connections" signs and take the transfer bus to Terminal 1. There will be another security screening there… but you'll go through immigration in Dublin.

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"I do not believe you have to to go through immigration at Heathrow "

You do.

Which is why travelhorizons has give the wrong link. You need:

http://www.heathrowairport.com/heath...lic-of-ireland

PS:

You also go through an immigration control in Dublin, though there is rarely any significant queue.

If you're just transiting at LHR why would you have to go through immigration? Wouldn;t you just stay airside - and go through Immigration when you get to Dublin?

In any case, I would make sure you have at least 2 hours to make that connection - more if possible.

>>why would you have to go through immigration? Wouldn;t you just stay airside - and go through Immigration when you get to Dublin?<<

Because AFAIK flights between the UK and Ireland are essentially considered domestic.

Well, if they're domestic - then why have to go through Immigration in Dublin.

And if the OP does have to go through Immigration and chnage terminals and check in again and go through security - I would want more than 2 hours.

>>And if the OP does have to go through Immigration and chnage terminals and check in again and go through security <<

The only thing in that list that applies is security.

>>Well, if they're domestic - then why have to go through Immigration in Dublin.<<

Because Ireland is an independent country and chooses to do so.

Ireland & the UK are in a Common Travel Area which gives free movement without passports for citizens of the Republic & the UK - but not for others.

As that means "domestic" passengers who are just flying UK to Ireland will be on the same flights as "international" passengers flying to Ireland via the UK, it becomes necessary for "international" passengers to pass through UK immigration

"Ireland & the UK are in a Common Travel Area which gives free movement without passports for citizens of the Republic & the UK - but not for others."

Bizarrely, not strictly accurate.

As far as the UK's concerned, there's no routine control over foreigners arriving from the Irish Republic, even foreigners who need visas to be here legally. But the political complications of the UK setting up passport control from Ireland are unacceptable, so the UK lives with the anomaly.

The Irish Republic, though is iffier about certain foreigners getting into Ireland via the UK, so it does impose passport control over air and sea arrivals from Britain - but not on land arrivals from Northern Ireland.

Both countries reserve the right to subject all arrivals (in Ireland, all arrivals from the UK: in Britain, all arrivals from anywhere in Ireland) to police checks on, or shortly after, arrival. This right is mostly invoked when Irish terrorists go into one of their self-indulgent fits of killing whoever they hate this week, though the Republic's police also randomly stop traffic from the North whenever they get worried about people-trafficking.

Like most of the ad-hoccery that's developed in official arrangements between the UK and Republic governments, it all sounds chaotic and illogical. But, by and large, it works.

The guide at http://www.heathrowairport.com/heath...lic-of-ireland , however it might sound in suburban New Jersey, is how Britain and Ireland manage their major air border.

No doubt the paradise for bullying bureaucrats the US has invented on its borders with Canada sounds more logical. We'd rather do it our way.

Our visitors agree.