Electronic Travel Authorization (ETA) for Heathrow Airport transit

The UK government states you do not need an ETA

https://www.gov.uk/check-uk-visa/y/usa/transit/somewhere_else

Is this on one ticket? (It doesn't matter if both flights are at Terminal 5) Did you book it as a continuous trip Washington to India or two separate flights Washington to London and London to India? What airline are you flying from London to India?

Will you have checked luggage?

Yes, this is on one single ticket from the US to India. I'm flying on Virgin Atlantic from US to England as well as from England to India. Yes, I will have checked luggage thar will be checked thru from US to India.

With a connection with one ticket you can remain airside at LHR even with checked luggage. That would also apply if you were changing terminals although in this case you aren’t.

Here is my only thought. Is there any possibility you might be going to the UK in the next two years? An ETA is easy to get, relatively inexpensive, and lasts two years or until you renew your passport, whichever comes first. In this day and age of irregular airport operations you might feel better knowing you could leave the secure area of the airport if you needed to.

Terminal changes can be done airside at Heathrow.

As noted you probably don't need one, but as Carol noted in this day and age, flight disruptions, strikes, or other travel drama might come up and it would ease my mind if I had an ETA so I could exit the airport if I needed to. It is easy to do, inexpensive, and would be a bit of travel insurance just the case.

Make sure you get the ETA through the official website and NOT via Delta airlines which directs you to a third party vendor (Sherpa) that charges an extra fee for something you can do yourself.

You don't need an ETA.

Even if something happened and your flight from London to India was delayed or canceled, you can still be admitted without an ETA. You will be processed by a Border Force officer rather than go through the egates.

But more than likely you will just stay airside.

Thank you for the valuable tips/insights, Carol/CL. It's a good point about getting the ETA if I'm planning to travel to the UK within the next 2 years. I AM actually planning an extended (3-4 months) visit to the UK in 2027 but my passport expires in 2026, so I think it would be better to renew it before applying for the ETA. Also, although I noticed that Delta was redirecting me to the Sherpa website for processing the ETA, I didn't realize that they are a 3rd party partner/vendor. I'm so glad I posted this question here, else I would have been unnecessarily paying for a middleman's services when I didn't need it. I'll apply directly on the UK Gov website, like CL recommended.