Dual citizen - which passport to use?

This one always does my head in.

I'm dual US-UK.

We'll be flying to Italy for a month on a one-way ticket.
I'll use my UK passport for that (passport details online for the flight and showing at the border). My US passport will stay safely tucked away.

We'll be flying on a return ticket Italy - US - Italy (through Heathrow, but we won't be leaving the airport) for Christmas.
Am I right to think that I should enter my US passport info in the online stuff for that flight (to avoid ESTA confusion) and show my UK passport when we re-enter Italy?

Yup!

I flew in/out of Italy this summer and there were both entry and exit passport controls.

So I would use your UK passport to enter and exit Italy.  But the US passport for your flight info and to check in for your US flight so no confusion around the ESTA.

OR you could just use your US passport the whole time.  No harm in that either.

When flying to the US i just tend to hand both passports over at check in.. Do the same coming back..
For me it is easier than remembering which to use when, even though i know US one on entering/leaving US and UK one entering/leaving UK ..

Others mileage may vary .. lol

This one always does my head in.

I'm dual US-UK.

We'll be flying to Italy for a month on a one-way ticket.
I'll use my UK passport for that (passport details online for the flight and showing at the border). My US passport will stay safely tucked away.

We'll be flying on a return ticket Italy - US - Italy (through Heathrow, but we won't be leaving the airport) for Christmas.
Am I right to think that I should enter my US passport info in the online stuff for that flight (to avoid ESTA confusion) and show my UK passport when we re-enter Italy?

That's probably what I would do 

That's probably what I would do 

+1

As long as you have both passports available there won't be any problem.

Cheers all!

I'm guessing it's the same protocol for UK/US flights - enter US passport details online and flash my UK passport when coming back to the UK?

I've already bookmarked this thread so I don't have to ask again next time! 

Cheers all!

I'm guessing it's the same protocol for UK/US flights - enter US passport details online and flash my UK passport when coming back to the UK?

Exactly.

As my daughter has both passports, I only use her UK one when entering the UK - just so she gets stamps.     My husband loves the stamps, so we figured we'd get her stamps.

The only exception has been when we were applying for our visas for China last year, I used her UK passport as it was cheaper.  BUT I didn't know that China has changed their rules and US citizens living abroad get a 10 year multi entry visa now.  So I should have spent the extra few ££ and got a 10 year visa for her!