Looking for suggestions on what to do on our first day in London

The first day in London, for me personally. has always been to take the tube to the Westminster station and ascend to the street level to immediately see the Houses of Parliament and its iconic Elizabeth Tower encompassing Big Ben. This kicks off my first day walking tour past Westminster Abbey through St. James Park until Buckingham Palace is reached. After the palace, walking up Pall Mall takes you past St. James Palace and toward the Diana, Princess of Wales Memorial Walk.

Continuing to the north end of Pall Mall brings you to one of Europe’s most spectacular public spaces at Trafalgar Square.

There are no lockers at Paddington. There is an Excess Baggage office next to Platform 12. £15 per item for 3 hours.

If Paddington Left Luggage doesn't suit you you can use one of the many other options available. I use RadicalStorage app to find them (and book and pay), but there are others.

Since you hav around 7 hours before you can get in, I would walk south, cross the Thames and walk east along the river. There are so many things to see there.

Continue to Tower Bridge. If you are lucky you can arrange to be there when the bridge lifts.

Cross the bridge and walk west towards your luggage.

Whenever you ar tired you can buy a cup of coffee and sit down to watch people rushing to work and enjoy that you are not one of them.

All along the way there will be tube stations and bus stops, so you can break the walk and go to your appartment, whn you feel like it.

Holland Park is handy for Notting Hill. As well as the park, there is Leighton House, former home of Frederick Leighton, one of the pre-Raphaelites and now a beautiful arts museum.
The park runs down to Kensington High Street, with it shops and restaurants.

One thing I have done successfully is take a London walks tour. The one I took was of Westminister area. I find I am okay physically but not as quick mentally when jet lagged and having someone else take me around worked well.

My standard first-day-in-London routine is a boat up the Thames to Kew Gardens. Beautiful day out (hopefully in the sun), which helps ward off jet lag.

But considering you're staying in Notting Hill, you already have my second thought, which is Portobello Road, particularly if you are there on a Saturday.

I think an 8 a.m. arrival is pretty optimistic especially if you have checked bags, plus you'll be traveling in the city during rush hour. Even so, my first choice would be to get an early check in at your apartment if you can. Second choice is your idea to store bags and get outside. I would store them closer to your apartment location so you are not backtracking to busy Paddington during a work day. You can use a bag service like Stasher or the other one mentioned earlier.

I'd probably get some breakfast at the airport before heading to the city to stave off hangry. Stash your bags, then take the tube to Westminster station and taking in the iconic sights of parliament, Big Ben, and Westminster Abbey. Walk over to St. James' park. You could then see the horse guards, and depending on timing you might see them returning from the Buckingham Palace changing of the guards (which is usually on Monday, but you would need to confirm for your travel dates). Find a light lunch and then make your way back to your accommodations which are hopefully available by then. On the way grab some groceries to stock your place, settle in a bit, and head out for a walk along Portobello road or head to Hyde Park. Grab some take away dinner (I liked the fish & chips from the Fish House of Notting Hill) and call it an early night.

I have had this same early arrival on 4 of my trips to London and seemed to get through immigration and baggage claim and transit to my hotel by 10 am or so. Freshen up a bit, leave my bags at the hotel and head right out for coffee, then the goal is to stay upright and outdoors until extreme exhaustion hits, usually by 5 pm. Assuming pleasant weather, I love to visit the Tower of London--the earlier you arrive, the less people, and there's lots to see and do, and a good long visit with the ravens is always the best start to my trip. From there I might head to Liberty and the Oxford St area to get a bit of shopping out of the way and have an early dinner at The Clachan and by then it's time to get into my room.

Other options could include a walking tour--https://www.walks.com/ London Walks offers an excellent variety every day of the week, or exploring St James Park and the Buckingham Palace area.

My last trip I had a companion who had never been to London so we decided the Tower would be on our second day, and went to Greenwich--lots to explore there, starting with the Market and a wonderful Sunday roast lunch at The Coach & Horses pub, walked up to the Observatory and explored a bit of the Maritime Museum, then around 4 pm we took the Thames Clipper back to Westminster--that allowed him to see a preview of the Abbey and Parliament, which we toured on another day.

Some clarity please. You are taking the HEX
( already reserved ? ) to Paddington. How are you traveling from there to your Nottinghill accommodation?

Depending on staffing at Heathrow Immigration
( not customs) your arrival may take longer than you expect. Commuter traffic ( tube, bus, taxi ) would be effected.

As mentioned no storage lockers at Paddington
( which is massive ). As suggested research what’s available closer to your Nottinghill accommodation for luggage storage.

Have you been provided intel from the property owner on best way from Heathrow. Specifically which tube station is closest?

Holland Park is lovely to amble about. So is Kyoto Gardens. Or you could also visit Kensington Gardens, the Round Pond and Kensington Palace.

The first time I ever went to London I did a hop on hop off tour bus. It was a great way to get acclimated to the city, know where stuff is, and the flexibility of having the time to do what you want and when. You can just stay on the bus and take it all in too!

A counter opinion on the hop on/hop off bus. I don't know how long ago the previous poster did this, but I can tell you that you end up paying to be in a traffic jam. Street traffic moves slowly through Central London and some of the hop on/hop off bus routes can take up to 10 minutes to circle a square and go the distance of 1 block.

Thanks all for the suggestion. I am leaning towards the idea of walking around Westminster. My wife and I have been before, but this will be the first time in London for my son, and I think it is a good intro.

Not sure I understand the difference between customs and immigration. Are there two separate lines we have to go through?
Since we are taking the Heathrow Express, I don't see how rush hour traffic would affect it. Once we get on the train, it is just a 15 minute trip with no stops between Heathrow and Paddington, correct?

Thanks for the tip on no luggage lockers at the station. I have already located a luggage storage place virtually next to the station. Yes, I do know exactly how to get to our apartment. We are located closest to Westbourne Park, or a short bus ride/15-20 minute walk to Notting Hill Gate. We travel light but may simply opt for a cab from the station to the apartment. With three people, for that short of a distance, the cab cost won't be that much more than public transportation.

I don't see any real advantage to finding a luggage storage place closer to the apartment. It is not likely to be on any of the residential streets around the apartment, so why take the time to go over there to drop off the bags, and then spend time making our way back to public transport when we are already at a convenient place to leave from?

Immigration is for people. This is where passports are checked and you're admitted to the UK. There will be officers directing US citizens to the eGates.

Immigration London Heathrow

Customs is for your stuff. If you’re carrying cash or goods of €10,000 or more, stop by the red customs exit to declare. Otherwise use the green exit if nothing to declare.

Thanks all for the suggestion. I am leaning towards the idea of walking around Westminster. My wife and I have been before, but this will be the first time in London for my son, and I think it is a good intro.

We also did this our first day in London. We used the Westminster walking tour on the Rick Steves Audio App. A good way to pass the time and stay outdoors.

Got it. I guess I always thought of immigration and customs as one thing with two parts, and in my mind the words were interchangeable.

Since we are taking the Heathrow Express, I don't see how rush hour
traffic would affect it. Once we get on the train, it is just a 15
minute trip with no stops between Heathrow and Paddington, correct?

Rush hour has to do with your onward travel from Paddington. Whether you go to your apartment or on to the central city, it's going to be busy. Now that you've narrowed down your closest tube stop people may have other suggestions. If you head to Westminster, you could have a couple of tube station changes, so make sure to have a good app like City Mapper to help you plot out your most efficient route.