Is 1 hour enough time for a connecting flight from nyc to Shannon at Heathrow?

If you mean a one-hour connection from JFK through Heathrow to fly onward to Shannon—no. I don’t think one hour is enough time for a transfer at Heathrow. If both flights are bought on one ticket, though, the airline is committed to getting you to Shannon. But if your JFK flight is delayed getting to Heathrow, you could easily miss the onward flight to Shannon and find yourself waiting four to five hours for a later flight. There are only a few flights each day from LHR to Shannon.

Buying separate tickets is definitely problematic.

Do both flights use the same terminal? Also, remember, you always go through security again.

You don’t mention the airline but as an example BA recommends 75 minutes for a through ticket connection in T5 and longer if you need to change terminals, 90 minutes I think. With two separate tickets I would want at least 4 hours.

Probably not. Heathrow is a mess and you really want 90 minutes - 2 hours for a transfer from the states to someplace else in Europe. We missed a connection in 2024 and had to spend 9 hours waiting for our flight to Glasgow. We would have been better off taking the train into London and transferring to a train to Glasgow. But if you are stuck in Heathrow, there are plenty of restaurants and shops.

It's not as simple as "I just have carry on."

A few questions need to be answered...

What airlines (2) are you flying? When we know this we will know if you need to change terminals.

Will this be on one ticket?

Keep this in mind. Aer Lingus is the only airline that flies nonstop from Heathrow o Shannon. It operates out of Terminal 2. Except for United, all other airlnes flying between NYC and LHR operate from different terminals. Changing terminals at Heathrow adds time.

Thanks everyone. I'm flying United from EWR to Heathrow, then Aer Lingus to Shannon. One ticket both ways. 4 hours going, almost 3 hours on the return trip. It seems both flights will be in/out of terminal 2, so I should be fine. BTW, United or Aer Lingus do not have direct flights. You have to change planes at Heathrow.

I appreciate the helpful feedback.

R

United has nonstop flights from Newark and Aer Lingus has nonstop flights from JFK.

I just checked.