Heathrow

Frequent question about getting through passport control. It depends on how many other flights arrived about the same time as yours. I’ve gone through in as few as 15 minutes, but as long as 2.5 hours. Generally, by the time you’ve gotten your passport stamped, your luggage is waiting for you.

For the second question, even if you don’t designate your ticket as a donation, you can still get it stamped so it will be good for a year. Before leaving the grounds, there is a small table right at the exit. Sign your ticket and get it stamped there. There is a person sitting there if you have any questions,

It’s always a crap shoot and it’s immigration not customs you will be clearing.

Seems you want to go straight to Windsor and want timely, cheapest and reliable transport. Not always a trio one can expect to find.

My first thought is if you are going straight from the airport where are you going to store your luggage.

In response to how to get there I’d opt for a taxi. No not cheap, but reliable and timely.

Or if arriving at Terminal 5 taking the bus but only if arriving at 5. That’s you cheapest option.

Here’s your options:
https://www.rome2rio.com/map/London-Heathrow-Airport-LHR/Windsor-Castle

No one knows the answer to some of your questions. First you go through immigration. This could take 5 minutes or it could take 2 hours.

Then you collect your bags. From there you walk through customs. Only once did I see anyone stopped in all the years I've been coming to the UK.

BTW...when you walk through customs you are clearing customs.

I do not know the answer to your question but piggybacking on your post because I had wanted to go straight to Windsor from LHR on our arrival day (we land at 7:20 am) next month. My issue is that it seems that there isn't luggage storage available in Windsor. Possibly they can hold some at the castle, but maybe not suitcases? Hoping someone may be able to comment on this aspect as well, or if anyone has done this I would like to know what they did with their bags.

There is a Left Luggage at Paddington, so maybe the best thing to do is get there via Heathrow Express or the Tube, whatever your preference, and then take the train from Paddington to Slough (transferring to Windsor). I admire your energy; we put off our Windsor trip until the jet lag subsided.

We are arriving at LHR around noon on a Thursday. Any thoughts on how
long it will take us to clear customs and pickup a bag?

Nobody can know in advance how long it will take you to disembark your aircraft, walk to immigration, know how many agents are working at immigration, guess at how many flights and people are ahead of you at the immigration line, and know how quickly your bag will pop onto the baggage carousel. It could take 20 minutes; it could take over 2 hours.

Customs is a walk through meaning no lines whatsoever so I'm not sure why you included that.

For a place to store your luggage, take a look at stasher.com or bagbnb.com. I haven't used these but they have good reviews and stasher shows two locations in Windsor. The castle also has a baggage storage room but it is a ten minute uphill walk to get there.

might be a very difficult one - just returned from london and when i arrived on 4/6 the custom was extremely slow, it took me almost 2 hr to clear. you should check the last admission to windsor, maybe 4:30 or 5pm.