ETA : Does the Airline check before one leaves or just the Border Force upon arrival

Yes. But you can’t board the plane without the ETA (assuming you need one).

You can book any flight before you have the ETA (refundable or non-refundable) or even your passport.

Per the UK website (https://www.gov.uk/guidance/apply-for-an-electronic-travel-authorisation-eta), ”You must apply for an ETA before you travel to the UK. You can travel to the UK while waiting for a decision.”

The ETA is applied to your passport. It's in the UK system. There is nothing to show the airline.

If you don't have one, the airline will get notice not to let you board. Or, you will get flagged when you go through immigration in the UK.

I bought my flight ticket many weeks before my flight. I applied for the ETA about 3 weeks before departure. My passport and ETA were checked at the gate. You should take this time into account and not go to the gate too late.

"*My passport and ETA were checked at the gate. *"

@Fjord: Which airport and how was this done? Do they just scan your passport and it shows you've got an ETA approval?

"My passport and ETA were checked at the gate."

Strange, given there's nothing to check. The check is electronic when they submit your API data on checkin. You arennot required to keep a copy of your ETA email. In several trips I've taken this year noone has ever asked me for it.

Although this won't apply to many travelers here, I was just reading on the Cruise Critic forum that Cunard is asking passengers sailing to the UK to

"Please carry proof of your ETA status (either a print out or a screenshot) for the duration of your voyage, as you will need to present this when asked."

I just returned from a trip to England and was not asked for any proof of my ETA. I assume it is connected to my US passport.

The ETA is connected to your pp so you are good to go when entering UK pp control.
We went to Spain after the UK and when we went to return from Malaga to London, they wanted proof at the gate that we had an ETA. We were told the gate isn't able to access the ETA on the pp and can refuse boarding. Fortunately the gate person believed me when I told her we had entered the UK previously and we were allowed to board. Another minute and I would have remembered I had proof of the ETA in an email file, but it was a very anxious moment. So, we now have a physical confirmation of the ETA plus a photo on our phones as we don't want to be in that situation again.

After reading the various comments, it seems like a few loose ends and wrinkles need some attention so things work the same everywhere.

Any US based gate agent here that can reveal what they see when they scan a passport at the gate ( or check in counter)?

But you can’t board the plane without the ETA (assuming you need one)

and

”You must apply for an ETA before you travel to the UK. You can travel to the UK while waiting for a decision.”

I cannot figure out how both of those statements can be true

Interesting. I wonder how they check people with visas if they don't have digital access? With evisas for the UK it's all digital, so no passport stamp.

I have Right of Abode, which is still a stamp in my passport, but my son has an Ancestry Visa, which is digital - nothing in his passport.

All the airports I've ever been to check visas/ETA on checkin, not at gate. Gate is just matching ID to boarding pass.

Airport was Frankfurt/ Germany
Airline Lufthansa
But I think the check was carried out by 4 British staff. It looked like a Pop-up counter without a computer. I had to show my ETA and my passport. This was checked against the passenger list and then I was allowed to go to the gate for boarding (where the Lufthansa checked the boarding ticket and my passport).

I had to show my ETA and my passport.

Did you show them the ETA email approval?

It is very concerning that airlines are asking for this because the email approval from the UK states, ” You do not need to print or show this confirmation email.”. What happens to people who follow this advice and don’t print or have access to the email?

@ AI

As a cautionary note, just make sure you do not have MS13 tattooed on your knuckles, or Photoshoped by the Whitehouse on any visible part of your body.

Regards Ron

I‘m a paper „fan“. Showed a paper ETA.
Sorry, forgot to tell. I was asked how long I want to stay in UK and I‘m not sure, but I guess he asked for the travel reason.

I had to show the email that my ETA had been approved before boarding the Europe bound flight. They let my wife through after I showed my email on my phone and she couldn't find hers.

All very interesting anecdotes. As someone above says, a few glitches in procedure that need to be ironed out. Rather surprising when the email ETA clearly states that there is no need to keep a paper record of the ETA.

Adding my experience in late March - no problem with on-line check-in United out of Chicago O'Hare, no requests at ORD United gate to see an ETA, no check on arrival at LHR. I understood that is the way the system is meant to work.

Unfortunately there may be little you can do on the day about rogue airlines etc inventing their own rules. The ETA email confirmation is not in any way a secure legal document and could be faked easily I would imagine (although for little benefit).

This is my understanding of the process.

All checking of ETAs is down to be done electronically, either submitting the data manually as part of a General Aviation Report (unlikely to be done for a large aircraft), or by submitting the data automatically via the Interactive Advanced Passenger Information. The latter could be done via use of a third party such as a ground handler.

Now this check returns the status of the passenger. BOARD and NO BOARD are self-explanatory. CHECK currently means a manual check of immigration documents as I guess there may still valid paper visas etc around. There is also an ERROR code where some of the data is missing etc and needs to be resubmitted.

CHECK also presently allows airlines to clear people to board if they have applied for an ETA but not yet received one and to get people to apply for one if they haven't. Both of these are short-term relaxation measures during the implementation period to treat sympathetically people who didn't know about ETA or found out at he last minute. At some time in the future these will be rescinded and the ETA will need to have already been approved without exception. These though won't have a conformation email indicating a successful application.