Enough time to make a connection?
 

I'm flying into LHR and due to how tickets were purchased, will need to clear customs before making connection to Dublin, Ireland. I have about three hours between arrival and subsequent departure flight. Is that likely enough time?

I don;t know the official minimum time - but IMHO I would not be happy with that little time - since there are so many ways you can be delayed:

Plane arriving late
Back up at Immigration
Delay for luggage arriving
transiting to the next terminal
Delays checking in luggage
Long lines at security

Are you sure there is no way you can have your luggage checked through to Dublin - so you can stay airside. For that your time should be good.

To have the best chance get a seat at the front of the plane, do not check any luggage and as soon as you are off the plane jog or trot to get to Immigration first.

If you have to 'clear customs' that means you also have to go through Immigration which is the much bigger issue. Plus - which terminals? Some are miles apart.

Obviously these are two different bookings -- so you are not at all protected. The good news is there are many flights a day to DUB. The bad news is (if you need one) walk-up fares are expensive.

>>Is that likely enough time?<<

Rather late in the game to be asking that question. But the answer is . . . maybe, maybe not.

Traveling carry-on only would help.

Where are you flying from? Will you have checked luggage? If you do, is it checked through to Dublin? Do you really mean clear customs or do you mean go through passport control? In any event, look at http://www.heathrow.com/flight-connections and enter the requested data and see comes up as what you need to do.

What are you going to do if you are told there is not enough time? If your action is the same if you are told there is enough time, then asking about it makes little difference in outcome.

It would be probably more productive to improve your chance of making the connection and reduce the damage if you don't.

Eliminate loss of time getting lost. Learn the airport layout. Find out which terminals your flights are likely to use. Study the transfer process.

Reduce chance of getting stuck waiting for your luggage and waiting at security. Reduce your luggage to carryon only.

Know all the options for alternate flight if you miss your flight.

Make arrangements at Dublin with more margin for delay. Know all the steps you need take to change arrangements at Ireland side that you can reduce damage if you had done it from LHR instead of waiting until arriving in Dublin. This means you need a communication method you can use at LHR.